Good question...

...does the savagery of predation in nature show that God either isn't, or at least isn't good-hearted?
[original piece: July 6, 1999  updated: July 18/1999]

There are several works that I will cite below, that are NOT in my personal library. Below are the ones that I will refer to by abbreviation:

[X01:FPvol8] Fish Physiology, volume VIII: Bioenergetics and Growth. W.S. Hoar, D. J. Randall, and J.R. Brett (eds.). Academic Press:1979.
[X01:FPvol5] Fish Physiology, volume V: Sensory Systems and Organs. W.S. Hoar and D. J. Randal (eds). Academic:1971.
[X01:FPvol6] Fish Physiology, volume VI: Environmental Relations and Behavior. W.S. Hoar and D. J. Randal (eds). Academic:1971.
[X01:FPvol4] Fish Physiology, volume IV: The Nervous System, Circulation, and Respiration. W.S. Hoar and D. J. Randal (eds). Academic:1970.
[X01:TP] The Predators. Irene E. Cohen, Putnum:1978.
[X01:AP] Animal Parasites. Jean G. Baer, McGraw-Hill:1971.
[X01:BP] The Biology of Populations. Robert MacArthur and Joseph Connell. John Wiley:1960.
[X01:PF] The Physiology of Fishes. David H. Evans (ed.). CRC Press:1997.
[X01:HBB] Hormones, Brain, and Behavior (Biology of the Reptilia). Carl Gans and David Crews (eds). UChicagoPress:1992.
[X01:BRvol8] Biology of the Reptilia, volume 8: Physiology B. Carl Gans (ed). Academic Press:1978.
[X01:BF] The Biology of Fishes. Q. Bone, N.B. Marshall, and J.H.S. Baxter. Chapman&Hall:1995.
[X01:BFCB] The Biology of Fishes. Carl E. Bond. SaundersCollege:1996 (2nd ed).
[X01:CBF] The Chemical Biology of Fishes, volume 2: Advances 1968-1977. R. Malcolm Love. Academic Press:1980.
[X01:EBF] Environmental Biology of Fishes. Malcolm Jobling. Chapman&Hall:1995]
[X01:PAI] Plant-Animal Interactions. Warren G. Abrahamson (ed). McGraw-Hill:1989]
[X01:WBFAR] Why Big Fierce Animals are Rare--an Ecologist's Perspective. Paul Colinvaux. Princeton:1978.
[X01:SLS] The Ecology of the Seas, D.H. Cushing and J.J. Walsh (eds.), W.B. Saunders:1976.
[X01:SME] The Structure of Marine Ecosystems, John H. Steele, Harvard:1974.
[X01:ME] Marine Ecology. Otto Kinne (ed.). Wiley-Interscience:1978.
[X01:MON] The Machinery of Nature. Paul R. Ehrich. Simon and Schuster:1988.
[X01:CDDAW] Carrion and Dung: the decomposition of animal wastes (The Institute of Biology's Studies in Biology no. 156). Roderick J. Putnam. Edward Arnold:1983.
[X01:IK] Innocent Killers. Hugo and Jane van Lawick-Goodall. Houghton-Mifflin:1971.


Question Two: How extensive is 'painful predation'? (In other words, DO all things live only at the expense of agonizing death by those lower on the food chain?)

Here we will have to cover a good bit of ecological and biological data...

The three keywords that I will organize this mass of data around are: "All", "Death", and "Agonizing".

First "Agonizing": All things live at the expense of agonizing death by those lower on the food chain.

What we have to do here is try to make some reasonable judgments as to what types of organisms actually can even 'experience' agony. Do the bacteria that my white blood cells engulf feel anything that could be remotely called 'agony'? Does the potted plant that I cut a flower from last week for my girlfriend still carry an emotional scar from the agony? Do the single-celled phytoplankton known as diatoms of the sea (without nervous system) feel torture as they are eaten by the slightly larger zooplankton?

Before we get into the data, we have to set out a couple of methodological points:

One, simple avoidance response to noxious stimuli on the part of an organism is not an adequate criterion for 'agony'. Single-celled organisms without a trace of nervous system (one rather obvious requirement for 'feeling' anything) manifest this behavior, but to predicate 'conscious agony' would be a stretch only a pan-psychist (or really consistent process philosopher) could make! The fact that a worm wiggles when stepped on will not be adequate evidence--by itself--for 'agony'.

ALL living things manifest was is called irritability [EBE, s.v. "Nerves and Nervous Systems: INTRACELLULAR SYSTEMS"]

"All living cells have the property of irritability, or responsiveness to environmental stimuli, which can affect the cell in different ways, producing, for example, electrical, chemical, or mechanical changes. These changes are expressed as a response, which may be the release of secretory products by gland cells, the contraction of muscle cells, the bending of a plant-stem cell, and the beating of whiplike "hairs," or cilia, by ciliated cells.

"The responsiveness of a single cell can be illustrated by the behavior of the relatively simple amoeba. Unlike some other protozoans, an amoeba lacks highly developed structures that function in the reception of stimuli and in the production or conduction of a response. The amoeba behaves as though it had a nervous system, however, because the general responsiveness of its cytoplasm serves the functions of a nervous system. An excitation produced by a stimulus is conducted to other parts of the cell and evokes a response by the animal. An amoeba will move to a region of a certain level of light. It will be attracted by chemicals given off by foods and exhibit a feeding response. It will also withdraw from a region with noxious chemicals and show an avoidance reaction upon contacting other objects."

But just "initiating a response" is too broad a term--sunlight 'initiates a response' in plant of cutting on the food-making engines, but this is not in the same category as the howling of a mammal whose leg is caught in a fur trap. The process of response initiation (e.g., nerve conduction or immediate chemical release) has to be considered.

Two, we are going to need some loci for the agony sensation to converge on, for there to be "something" to experience "agony".

Let me illustrate what I mean by this from personal experience. In the early 1970's, I had a small growth removed from a joint in one of my fingers. The operation was done in an outpatient setting, with me being fully awake. They wrapped a rubber tube/band around my bicep, essentially cutting off most 'communication' between my brain and my hand. They then fed a powerful anesthetic into that section of my arm. They then did the 'slice and dice' on my hand, with deep incisions and peeling skin back and all that. But I didn't feel a thing--whatever sensations would have been 'agony' never reached 'me'. For all practical purposes, my nervous system was functioning as a 'segmented' nervous system. Did my arm 'feel agony', as violence was being perpetrated on it? Not by any current definitions of pain.

This, of course, is how anesthesia sorta works--it keeps the 'bad news' from reaching some higher-order, self-aware nerve integration point. There was certainly cell damage and "screaming" nerve transmissions, but my arm didn't try to defend itself because its motions are controlled by an agency "beyond the rubber tube line."

What this will imply for our study is that only organisms with non-segmented nervous systems and with some central integration site will be candidates for having something "there" to experience agony.

Three, from the above situation we can also infer that cell damage or destruction (and possibly even death itself) is not an adequate criterion for experiencing agony. If the nerves and the skin and the muscles and the vascular system of my hand were being sliced open by the scalpel, and yet I felt no agony at all because no 'signals' were reaching my center of consciousness, then the fact of damage alone cannot serve to differentiate between agony and non-agony. If whoever kills me first anesthetizes me, then my death cannot be perceived as 'agonized'.

Okay, these are reasonable starting points, so let's look into the natural world to make some initial cut at separating the non-pain-feelers from the pain-feelers.


We have five Kingdoms to examine:

1. Monera (Prokaryotes). Mostly single-celled bacteria. Thousands of species. No central nucleus. No nervous system at all, but manifests basic irritability (general avoidance motion) to noxious stimulus. No reason at all to believe that this little cell experiences 'agony' at dissolution.

2. Protista (Eukaryotes). Mostly uni-cellular with-nucleus species (but some colonial forms also). "Some of these organisms are animal-like (protozoans), others resemble plants (algal protists), and still others demonstrate the characteristics of fungi." (NS:SOB:377). Protozoans (thousands of species) have no recognizable nervous system, but can respond to various stimuli with chemical changes (e.g., motion can be started by an external stimulus changing texture of the cytoplasm [NS:BPS:330], not remotely akin to nerve impulse conduction and response.) Algal Protists (over 25k species) are plant-like, with some multi-cellular organisms. Especially important are the diatoms and dinoflagellates, which produce 3/4th of all organic material in the world! [NS:PSB:196].Fungi-like protists are basically slime molds. Many of these species reproduce by fission--the elongation and division of the cell nucleus (if somehow the 'adult' nucleus was 'sensitive' to pain, what a painful process elongation and division would be every reproductive cycle of 20 minutes or so!!!). Again, nothing here to suggest an 'agony-capable' conscious center.

3. Fungi (multi-cellular or multi-nuclear, except yeasts) They absorb food rather than ingest it (they secrete digestive fluids outside their bodies and absorb the resulting solution), and are limited in mobility. Includes yeasts, molds, and mushrooms. Over 100,000 species. No structures to support an 'experience of agony'.

4. Plantae (plants). These are divided into bryophytes (non-vascular) and tracheophytes (vascular). The non-vascular plants are mosses, liverworts, and hornworts. They lack structures to 'stand up' so they hug the ground. They are photosynthetic, though, and comprise around 18,000 species. The vascular plants are the ones we are most familiar with, with around 260,000 species.

There are three areas of plant irritability that would be closest to 'sensation' or nervous system function: tropisms, triggers in rapid touch-response plants (e.g. Venus Flytrap), and induced responses to herbivory.

(1) Plants do not have nervous systems, but do manifest a higher level of irritability called tropism:
  "A tropism is an invariable growth response to an environmental stimulus occurring in plants and primitive invertebrates. It is a relatively unsophisticated type of irritable reaction. Irritability is the capacity to respond in characteristic ways to changes in the environment. The complex repertoire of often subtle voluntary responses associated with irritability in primates affords a far greater range of adjustments to the environment than is the case with tropisms, which are stereotyped and limited types of behavior.

"Tropisms are named from the eliciting stimuli and described as 'positive' if growth is toward the eliciting stimulus and 'negative' if growth is directed away from the stimulus...Responses to gravitation (geotropism), water (hydrotropism), light (phototropism), pressure, touch (thigmotropism), etc. are crucial to the survival of a plant.

"The tropisms, as well as a number of other phenomena occurring within the plant, are probably mediated by plant hormones. A hormone is a substance produced in one part of a living organism that has profound metabolic effects of function and behavior and generally involve relatively slow responses as compared with the faster neural responses, which are found only in animals." [NS:SOB:197]


"Most animals perceive external stimuli via specialized sense organs and respond with the aid of an elaborate nervous system. Plants have neither sense organs nor nervous systems, but react to stimuli by means of tropisms. A tropism can be defined as a growth movement effected by an actively growing plant in response to a stimulus coming from a given direction. This results in the differential growth or elongation of the plant toward or away from the stimulus." [NS:BPS:282].

Needless to say, there is a HUGE difference between a "growth response" and an "agony response"...

(2) The closest we get to a neuronal firing or nerve impulse among plants might be in the Venus Flytrap and mimosa plant. These show very rapid responses to touch, but do not use muscle tissue and efferent nerves, of course. The signal mechanisms are probably electrical traveling down sieve tubes and altering permeability of plasma membranes, flushing fluids from cells which creates the movement. These are elaborate mechanical systems, with loose analogs in some lower vertebrate forms. This is still way too far from sympathetic nervous systems to be considered even 'pain possible'.

(3) Induced responses to herbivory [NS:IRH] is a relatively new area of research, which studies what physiological changes occur in a plant as it is being eaten and/or after it has been eaten (actually, it also includes a wider range of threats that just herbivory). This fascinating subject attempts to find signal mechanisms for damaged parts (e.g., leaves) to send throughout the plant to "induce a response." The basic mechanism for this involves chemicals in plant cells which are broken loose by chewing. These chemicals combine with other chemicals in the surrounding plant cells, creating compounds (e.g., systemin) that are transmitted through the plant, triggering various responses (like hormones) such as the production of proteinase inhibitors [NS:IRH:80f], and of increased rates of photosynthesis [NS:IRH:51]. All of the signaling mechanisms being investigated are chemical (the responses of plants are too slow for electrical signals to be the mechanism [NS:IRH:35]), so this response is similar to tropisms, in their "non-cognitive" status [NS:IRH:12]

Accordingly, we have absolutely no warrant to believe that plants "feel" anything (with no even remote analogs to animal sensation), and have warrant to believe that though they "adjust to" tissue damage, they do not 'feel' this per se.

5. Animalia (animals). Here we need to get a little finer detail, because we will begin running into real nervous systems soon. For simple breakdown purposes:

A. Invertebrates (90% of all animal species are in this): Ranges in organizational complexity from the simple sponges (more colonial in organization than unitary) to 'mid-range' Annelids (worms) to the most complex organism in this class the Insect. In this broad group we begin to see nervous systems, although of simpler and segmented types. The Insects are the dominant group here numerically, comprising over a million species (experts believe that the actual number of species may be 2-4 times that amount). They represent 84% of all living animal species.

Although the squid and octopus are quite well-developed from a nervous system point of view (the octopus is a frequent experimental animal in learning studies), their brains are actually fused ganglia, enabling high levels of coordinated activity/response [NS:AWB:282]. They have many specialized neural developments (on a functional level matching some lower animals) and might be considered to be on a par with the insects in nervous system sophistication. (Some actually put them up higher, with the fishes.) However, the integration of internal sensory data (a requirement for 'suffering') is lacking: "Among other invertebrates, the cephalopod Octopus clearly exhibits proprioceptive abilities, though specific receptors have not yet been identified. These animals, however, seem unable to integrate proprioceptive data in the central nervous system with other sensory information in learning. Thus an octopus readily can be taught to discriminate between two small cylindrical objects (both provided with longitudinal ribs) if the ribs on one of them are somewhat coarser than those on the other. But the animal cannot learn to distinguish between cylinders of the same size if the ribs are equally coarse and if they are longitudinal on one and transverse in the other; nor can it learn to discriminate between small objects of different form or different weight. This indicates that an octopus cannot learn any discrimination that depends on sensory information about the position of the arms and suckers making contact." [EBE:s.v. "Sensory Reception:Invertebrates].

Similarly, the nervous systems of the stinging-cells animals are too specialized to be considered a "conscious" CNS [NS:AWB:111ff]. So, from a generalized brain-complexity standpoint, Insects are still the high-water mark so far in our discussion.

The annelids (e.g., worms) have an elaborate nervous system, but it is massively segmental (like me and my anesthetized arm), and the brain functions as an integration center for a couple of the sensory lines. The stimulus-response system is widely distributed between the brain, the first ventral ganglion, and the segmental ganglia. The brain doesn't seem to have the importance for the worm that we 'need' for agony:

"The brain appears to direct the movements of the body in response to sensations of light and touch. And it has important inhibitory functions, for if it is removed the worms move continuously, but otherwise their behavior is affected little." [NS:AWB:300] (emphasis mine) The lobster nervous system is segmental, like the annelids.[NS:AWB:329]

The spider also seems to be without the ability to experience pain:

"During the act of copulation the male (tn: Australian redback spider, relative to black widow) does a somersault in which he places his abdomen directly over the female's mouthparts. If she decides to eat him, she does so while he is in this position. Significantly, copulation lasts about twice as long if the female is engaged in devouring her mate than if he escapes with his life." [NS:RAL:161]
The insects, although the "highest" form in this invertebrate class, are still without adequate nervous systems to experience agony:

First, their equipment still seems too distributed or segmental:
"The nervous system is a ventral, double, ganglionated cord. The brain lies above the esophagus and between the eyes. It is joined to the first ventral ganglion by a pair of connectives that encircle the gut. The brain has no centers for coordinating muscular activity; after removal of the brain the animal can walk, jump, or fly. As in other invertebrates, the brain serves as a sensory relay that receives stimuli from the sense organs and, in response to these stimuli, directs the movements of the body. It also exerts an inhibiting influence, for a grasshopper without a brain responds to the slightest stimulus by jumping or flying--a very unadaptive kind of behavior. And even in the absence of any external stimulation, the animal without a brain displays incessant activity of the palps and legs. In addition the brain is responsible for certain complex behavior patterns and for modifying them by learning. The first ventral ganglion controls the movements of the mouth parts and exerts a general excitatory influence. The segmental ganglia are connected and coordinated by nerves that run in the cords, but each is an almost completely independent center in control of the movements of its respective segment (or segments) and appendages. In some insects these movements have been shown to continue in segments that have been severed from the rest of the body. An isolated thorax is capable of walking by itself, and an isolated abdominal segment performs breathing movements." [NS:AWB:378]
What this shows us is that the "feeling" is de-centralized (along with much of the motor control). This suggests that the "internal communications network" is relatively inadequate for detecting internal pain (as opposed to external food or a potential mate, for example).

Second, we have concrete indications that they do NOT feel internal pain:

"Some insects normally show no signs of painful experience at all. A dragonfly, for example, may eat much of its own abdomen if its tail end is brought into the mouthparts. Removal of part of the abdomen of a honeybee does not stop the animal's feeding. If the head of a blow-fly (Phormia) is cut off, it nevertheless stretches its tubular feeding organ (proboscis) and begins to suck if its chemoreceptors (labellae) are brought in touch with a sugar solution; the ingested solution simply flows out at the severed neck. [EBE:s.v. "Sensory Reception: Mechanoreception"]

This is not altogether unreasonable at all. We know that even humans have tissue that is insensitive to certain types of pain:

"In spite of its subjective nature, most pain is associated with tissue damage and has a physiological basis. Not all tissues, however, are sensitive to the same type of injury. For example, although skin is sensitive to burning and cutting, the viscera (internal organs) can be incised with a knife or laser without pain being generated. Overdistension of a hollow viscus or chemical irritation of the visceral surface, however, will induce pain. Some tissues do not give rise to pain, no matter what the stimulus; the parenchyma of the liver and the alveoli of the lungs are insensitive to almost any stimulus. Thus tissues respond only to the specific stimuli they are likely to encounter and are not generally receptive to all types of damage." [EBE:s.v. "pain"]

Also, the number of nerves in the abdomen of the typical insect is quite small--most are concentrated on the exterior of the insect.

So, what can we say about the experience of agony here, when an insect suffers tissue damage? Do we have reason to believe that the insect's nervous system 'feels pain'? The above data argues quite strongly that we don't. In spite of the complex behaviors possible, and in spite of the advanced sensing abilities of these species for food detection, the data is still overwhelming that they are either not aware of internal tissue damage, or are not 'agonized' enough by it to initiate action (e.g., stop eating their own abdomen!)


Now, before I get into the more difficult groups (e.g. fishes), let me take stock of where we are:

1. With the possible exceptions of the advanced cephalopods (squid and octopus), all the species we have talked about so far have no 'equipment' with which to experience agony.

2. We actually have data that the highest form of life discussed so far does NOT experience pain during massive tissue damage.

3. The above conclusions apply to ALL the plant species (280,000), to virtually ALL the invertebrate species (1,100,000), and to ALL the lower species (140,000).

4. We have yet to discuss the vertebrates, which comprise around 45,000 species (half of which are fishes).

5. So, 1.5M species of life on earth cannot experience agony". This represents 97% of all living species (and, I might add, several orders of magnitude greater number of individuals ( and biomass--a matter we will discuss later).


Okay, back to the detail...

B. Vertebrates. We have 45,000 species here to look at with approximate breakdowns of fishes (20k), amphibians (4.5k), reptiles (6k), birds (8.7k), and mammals (4k).

At the "high" end, we can be reasonably assured that higher mammals can experience intense spikes of pain. They certainly have the central nervous system components, capacity for emotion (CS:WEW, although this is decidedly a one-sided look), and have various levels of self-awareness [CS:AM:248ff, but note the criticisms of this approach in NS:AAA:335-339]. [A good example would be animals that limp when a leg is injured. In normal circumstances (e.g., when they are not trying to trick a predator by acting injured, as female birds and moose regularly do), this would indicate that pain was a real experience.]

At the "low" end (i.e., fishes), the data seems to indicate that fish can experience physiological stress, but the subjective 'pain' experience of this is quite doubtful. (We also have some specialization/segmental issues here as well). We will review the data closely, but in addition to our grave doubts about their experience of agony, it also appears that the time delay between negative stimulus and the consequent internal 'stress' symptoms is so great as to make 'sudden death' virtually painless.

[One interesting piece of information here comes from a pet/vet store, specializing in goldfish. They have a web page ( describing euthanasia for koi goldfish. Look at what they consider to be 'merciful' and 'least painful' ways of terminating the koi:

"Euthanasia should be considered when a fish is intractably ill or deformed by disease beyond hope of salvation. Even though it is believed a fish feels no deep pain, if they are hopeless, euthanasia is a humane choice. Ideally, hypothermia is the recommended way to dispatch a fish. Place the fish in a modest amount of water so that it may recline upright and comfortably. Place the bowl or bag in the freezer and close the door, providing darkness. As the poikilotherm (cold blooded animal) loses heat, the enzymes that govern consciousness are inactivated and they lose sensation and finally all systems arrest, painlessly and completely. Alternatives would involve severing the head behind the gill covers. For larger fish, a sharp blow (with hammer or other weighty object) to the head between the eyes is effective. Then the head is severed."]

Let me try to organize this material under the following heads:

1. The gap between the low-end and the high-end of the vertebrates is substantial--fish are quite different than mammals:
"One reason for choosing the fish as subject in such studies (i.e. learning) is the animal's greater 'simplicity' as compared to mammals. The absence of a highly developed telencephalon [tn: "the front and largest part of the forebrain in terrestrial vertebrates. It is largely devoted to associative activity."] and the presence of a well-developed hypothalamus [tn: regulates the body's internal state] make the fish a particularly attractive subject for certain problems." [X01:FPvol6:261]

" rats subjected to extreme decortification as infants showed no improvement in habit reversal: They became, in effect, like fish in this respect." [X01:FPvol6:225]

"A striking difference between the spinal cord of adult fishes and those of terrestrial vertebrates is the absence of large numbers of proprioceptive [tn: "sensory receptor that responds to physical or chemical stimuli originating from within the organism. In vertebrates, proprioceptors supply the cerebellum with information about the position and movements of body parts."] fibres from muscle spindles. These seem not to be found in fishes." [X01:BF:270] (Notice here, that the main things we need, other than a brain, to be able to know we are hurting inside is a good, detailed set of proprioceptive nerve/fibers. Without these, the brain doesn't get any quick signals.)

"The regenerative capacity of the spinal cord of fish was unparalleled among the vertebrates. This capacity extended from the simple regrowth of axons across the lesion to reconstitution of the parenchyma into the former neural cytoarchitectonics and complete restitution of new nerve cells and glia." [X01:FPvol4:74f]

2. Much of the 'intelligence' in fishes is dispersed, being distributed to the spinal cord and specialized 'hard wired' systems (as we saw in the invertebrates). This argues against a truly 'central site' sense of pain.
  Fish spinal cords regenerate, with function, even in larvae, within days. [X01:FPvol5:337]..."Spinal cord regeneration in larval and adult fish was both anatomically and physiologically successful. The regenerative capacity of the spinal cord of fish was unparalleled among the vertebrates. This capacity extended from the simple regrowth of axons across the lesion to reconstitution of the parenchyma into the former neural cytoarchitectonics and complete restitution of new nerve cells and glia." [X01:FPvol4:74f]...

"Transection of the entire motor root of the trigeminal nerve resulted in complete paralysis of the jaw. However, within 16 days, mandibular movement had returned to normal." [X01:FPvol4:76]

Cerebellum removal in whole or part (of fishes) sometimes increased response to painful and non-painful stimuli (advanced fishes) and sometimes suppresses it (dogfish). In each case, the functional loss is regained (mostly) in less than a day. [X01:FPvol4:51f]

"Evoked responses induced by acoustic stimulation (clicks) were recorded only from the medulla oblongata and never from other parts of the brain." [X01:FPvol4:56]

"It appears that the caudal neurosecretory system [tn: in the rear of the fish] is a neural center within the spinal cord whose discharge to its endorgan (urophysis) results in the release of substances that regulate the osmotic balance in fish." [X01:FPvol4:72] but "suggests that the center regulating the electrical activity of the caudal neurosecretory system is within the brain proper."[X01:FPvol4:74]

But the vascular system might be under sympathetic (tn: prepares the body for stress) control. [X01:FPvol4:124]

"the CNS is perhaps the most daunting of any other system in the fish, for not only does it contain astonishingly large number of specialised cells in great variety, but the complications of their connections and interactions are great." [X01:BF:264]

"In sharks, destruction of the brain does not immediately cause paralysis, as it does in lampreys and teleosts. Instead, such 'spinal' sharks continue a stereotyped slow swimming pattern for many hours." [X01:BF:268]

If L-DOPA is added to a vat of lamprey spinal cords, they start trying to swim! [X01:BF:268]

"To some extent, the brain can be regarded as an enlarged anterior portion of the spinal cord with hypertrophied centres associated with the development of input from the special sense organs." [X01:BF:271]

So many hard-wired, reflex functions: Mauthner systems (startle response), mesencephalic V (jaw close)...[X01:BF:283-286]

"Autonomic fibres reach almost all parts of the body, and regulate visceral functions to maintain homeostasis." [X01:BF:290]

"The following observations illustrate some of the difficulties in making judgments of the inner experiences of creatures other than man. After the spinal cord of a fish has been cut, the front part of the animal may respond to gentle touch with lively movements, whereas the trunk, the part behind the incision, remains motionless. A light touch to the back part elicits slight movements of the body or fins behind the cut, but the head does not respond. A more intense ("painful") stimulus, however (for instance, pinching of the tail fin), makes the trunk perform "agonized" contortions, whereas the front part again remains calm. To attribute pain sensation to the "painfully" writhing (but neurally isolated) rear end of a fish would fly in the face of evidence that persons with similarly severed spinal cords report absolutely no feeling (pain, pressure, or whatever) below the point at which their cords were cut. [EBE: s.v. "Sensory Reception: Mechanoreception"] Notice the obvious non-parallel with humans: in the case of humans with spinal injury, the bottom half of the body does not 'writhe' under any such circumstances--there is no 'intelligence' in our spinal cords as is in fish.

3. Most sensory 'equipment' is directed externally from the fish, toward feeding and predator detection. Internal and visceral sensation is not as developed, and fish response to stress is slow.
  In the lower forms of fish (cyclostomes): Many hagfishes have no sensory nerves in the heart (whereas lampreys do, but not larval ones), and the data is divided relative to much of the trunk. [X01:FPvol4:110]

In the higher fishes, the nerves are parasympathetic and "it is well established that there are no distinct sympathetic nerves innervating the heart directly." [X01:FPvol4:117]

Many functions of internal organ function (i.e., gastric, hepatic, pancreatic secretion) are not under nervous control at all. [X01:FPvol4:119]

"Wilber and Sudak found that there were no compensatory cardiovascular responses to hemorrhage in Mustelus and Squalus." [X01:FPvol4:125]

"The innervation within the longitudinal muscle layer is sparse." [X01:PF:296]

"The hormones themselves (pituitary-adrenocortical) take an appreciable time to increase. Stressed Carassius auratus do not show a rise in serum cortisol [tn: anti-inflammatory chemical] until 10 to 22 minutes after capture. Singley and Chavin showed that when Carassius auratus are acclimated to their environment, no method of capture will affect the serum cortisol levels provided that the time from capture to death is less than 3 minutes. Similarly, neither immobilisation in ice, anesthesia in MS 222 (tricaine methane sulphonate) nor electrical immobilisation affect the level." [X01:CBF:235]

One research study showed a delay period of 40 minutes before a rise in serum cortisol [X01:CBF:236]

"A striking difference between the spinal cord of adult fishes and those of terrestrial vertebrates is the absence of large numbers of proprioceptive [tn: "sensory receptor that responds to physical or chemical stimuli originating from within the organism. In vertebrates, proprioreceptors supply the cerebellum with information about the position and movements of body parts."] fibres from muscle spindles. These seem not to be found in fishes." [X01:BF:270]

One research scientist at AquaNic ( put it this way: "Pain is transmitted by specific neural pathways and receptors for pain may be activated by mechanical, thermal, or chemical stimuli. Fish possess these types of receptors in their skin. In humans, pain is sent to higher brain centers (prefrontal cortex) where it is perceived and the perception is associated with a powerful emotional experience. Fish, however, do not possess these well developed higher brain centers and thus they probably perceive a painful stimulus and react to it almost as a reflex. After the initial perception, they would not be bothered by the stimulus, similar to what occurs in humans who have had surgery to central brain regions to treat chronic pain."

4. The presence of opioid and similar drugs (which are associated with pain reduction in humans) do not imply pain-issues in fish. Rather, they have their more basic functions of respiratory depression and control of blood flow to the gut. [X01:PF:297]

5. Fishes are generally r-selected, which means that most fish die in their infancy (mostly egg and larval stages). Those that survive this period, generally live relatively long lives. The nervous system of these high-mortality infant fish is even less developed than that of adult fish.

"There are fewer nerve fibers present in the embryonal or newly hatched fish than in adults, and the distribution is slightly different. It has been suggested that the nerves that appear before hatching are involved in the control of cell growth and proliferation, but after hatching their role changes to the control of food processing." [X01:PF:297]

The spinal cord of fishes undergoes development during the larval stage. [X01:FPvol4:68ff]

"Although embryonic and larval fish have very large numbers of neurons in the transient Rohon-Beard system, these all disappear at metamorphosis, and are replaced by the sensory neurons of the dorsal root ganglia. [X01:BF:270]

"Locomotor powers of larvae are not great, and prey is detected at one body length or less during early feeding." [X01:BFCB:479]

"Maturation of sensory organ systems aids in detection of predators." [X01:BFCB:480]

In light of the above, I have to conclude that:

1. Adult fish do not experience 'agony' in a way comparable to the higher mammals, if they do at all. (The nervous system equipment is simply not there).

2. Young fish experience even less sensation than adult fish.

3. Internal non-reflex responses to stress are quite slow.


The next group up is that of the Amphibian. Although their CNS "is more like ours" and certainly able to do very, very complex behaviors, we still have strong evidence that their visceral (tn: internal) sensory mechanisms are not very pain-sensitive:

"It has been reported, however, that a frog placed in a pan of cool water will not jump out as the pan is heated, if the temperature changes are gradual enough. Indeed, frogs are recorded to remain in the water this way until they are boiled to death. [EBE: s.v. "Sensory Reception: Amphibians and reptiles"]

And evidence that we still have highly distributed systems at work:

"For example, a decapitated frog reacts to stimulation of the skin by precisely directed limb movements aimed at wiping away the stimulus [EBE: s.v. "Sensory Reception: ANIMAL SENSORY RECEPTION"] (Notice the similarity to the 'writhing' of the spinally divided fish)

This data seems to indicate that we are still down there with the fish...


The next group contains the Reptiles. These are cold-blooded (like the fish and amphibians), but along with the Amphibians, they manifest a similar situation:

"But if simpler nervous systems have more of a one-to-one correspondence between neuron and behavior, where does that leave them regarding consciousness? Let us return again to the transition in and out of unconsciousness. Turbellarian worms and planaria, crabs and lobsters, octopuses and squids, houseflies and butterflies do not sleep as we do. They "rest" for brief periods of time, but this is a very different state from the one we recognize as sleep. Similarly, neither fish nor amphibians display any electrical signs of brain sleep (Hobson 1989). Perhaps in creatures where the unconscious state, the rest period, is not so dramatically different from the awake, moving period, the degree of consciousness may not be very developed and extensive. Indeed, the degree of consciousness might be so vestigial that it is as if there were none [CS:JCM:79-80].

Although brain size arguments can be controversial, in the case of the Reptile the scale difference (in the main associative part for consciousness/sentient experience) is too great for us to expect much consciousness:

"As in all vertebrates, the nervous system of reptiles consists of a brain, a spinal nerve cord, nerves running from the brain or spinal cord, and sense organs. Reptiles have small brains compared with mammals. The most important difference between the brains of these two vertebrate groups lies in the size of the cerebral hemispheres, the principal associative centres of the brain. In mammals these hemispheres make up the bulk of the brain and, when viewed from above, almost hide the rest of the brain. In reptiles the relative and absolute size of the cerebral hemispheres is much smaller. The brain of snakes and alligators forms less than 1/1,500 of the total body weight, whereas, in mammals such as squirrels and cats, the brain accounts for about 1/100 of the body weight. [EBE: s.v. "Reptiles: Nervous System"] ......................................................................................................................................................................................

The next group contains the Birds. These are warm-blooded (like mammals).

These are more difficult (theoretically) for me than the others. As warm-blooded, they have to pay more attention to their internal states, their CNS is more developed, and their significantly increased parental care (relative to "simpler" forms) almost encourages 'anthropomorphism'...The strongest evidence I can find for some higher thinking (or experience) comes from the long-term (but apparently still unique) work of Irene Pepperberg and her parrot Alex [see the discussion in CS:AM:171ff].

So, I am going to half-include them in the "spectrum of consciousness" (but with serious reservations).


Finally, we get to Mammals. It is here that the greatest controversy occurs. Animal behaviorists/ethologists and naturalists (and many pet owners!) argue for rather high levels of consciousness and emotion, whereas those that study comparative neuroanatomy generally shy away from this.

So, naturalists and zoologists write books like When Elephants Weep--The Emotional Lives of Animals [CS:WEW], Animal Minds [CS:HI:AM], and Good Natured--The Origins of Right and Wrong in Humans in Other Animals [ PH:GN], describing behavior that is more easily "explained" by anthropopathic approaches.

And, on the other hand, neuroscientists still point to the major difficulties of assigning consciousness to non-primates (and sometimes primates, as well). Representative evidence and statements are:

"An early and overly zealous brain researcher, E L. Goltz, in an experiment straight out of a horror movie destroyed a dog's brain by means of a jet of water injected under high pressure through a hole in the skull. Goltz and the animal toured together in a kind of macabre road show to various medical meetings. When placed on the demonstration platform, the dog made no movements and appeared to be asleep. Noise would wake it up, a painful pinch would cause it to growl. When placed upright, it would walk in a mechanical way and would swallow food put in the back of its mouth. Otherwise the dog didn't act much like a dog, took no notice of its surroundings, and, most importantly, carried out no actions that could be even remotely considered voluntary[CS:TMB:39] [Notice that irritation was somehow independent of the mammalian brain--like the case of the decapitated frog...]


"We know that there is a great deal of similarity in brain organization across the various vertebrate species. ALL vertebrates have a hind-brain, midbrain, and forebrain, and within each of the three divisions, one can find all of the basic structures and major neural pathways in all animals. At the same time there are obvious differences between the brains of widely different groups of animals. Species differences can involve any brain region or pathway, due to particular brain specializations required for certain species-specific adaptations or to random changes. However, as one follows brain evolution from fish, through amphibians and reptiles, to mammals, and ultimately to humans, the greatest changes appear to have taken place in the forebrain. But evolution should not be thought of as an ascending scale. It is more like a branching tree. The long process of human brain evolution has not just been a matter of making the forebrain bigger and bigger; it has also become more diversified. For example, as we saw in Chapter 4, it was long thought that the neo-cortex was a mammalian specialization, one that did not exist in other classes of animals (the designation "neo" reflects the supposed evolutionary newness of this part of the brain). However, it is now known that all vertebrates have areas of the cortex that correspond with what is called the neo-cortex in mammals--these are just located in a different place in non-mammalian species (birds and reptiles, for example) than in mammals, which caused anatomists to misjudge what these regions are. Nevertheless, there are areas of the human neo-cortex that are apparently not present in the brains of other animals. [CS:TEB:123]

"Throughout this discussion of the evolution of emotion, I've said nothing about what most people consider the most important, in fact, the defining feature of an emotion: the subjective feeling that comes with it. The reason for this is that I believe that the basic building blocks of emotions are neural systems that mediate behavioral interactions with the environment, particularly behaviors that take care of fundamental problems of survival. And while all animals have some version of these survival systems in their brains, I believe that feelings can only occur when a survival system is present in a brain that also has the capacity for consciousness. To the extent that consciousness is a recent (in evolutionary time) development, feelings came after responses in the emotional chicken-and-egg problem. I'm not going to say which animals are conscious (which ones have feelings) and which ones are not (which ones don't have feelings). But I will say that capacity to have feelings is directly tied to the capacity to be consciously aware of one's self and the relation of oneself to the rest of the world. [CS:TEB:125]


"But no matter how firm or flimsy the arguments about consciousness in other humans are, when it comes to making the leap to the minds of other animals, we are on considerably shakier ground. Our ability to hold conversations with other animals is somewhere between not at all and not much. And while our brain is, in many ways, incredibly similar to the brains of other creatures (this is what makes much of brain research possible), it also differs in some important ways. The human brain, most especially the cerebral cortex, is much larger than it should be, given our body size. This alone would give us reason to be cautious about attributing consciousness to other animals. However, there are other facts to take into account. First, as we've seen, the part of the human cortex that has increased in size the most is the prefrontal cortex, which is the part of the brain that has been implicated in working memory, the gateway to consciousness. Some brain scientists believe that this part of the cortex doesn't even exist except in primates. And there is behavioral evidence that only the higher primates, in whom the prefrontal cortex is especially well developed, are self-aware, as determined by their ability to recognize themselves in a mirror. Second, natural language only exists in the human brain. Although the exact nature of the brain specialization involved in making language possible is not fully understood, something changed with the evolution of the human brain to make language happen. Not surprisingly, the development of language has often been said to be the key to human consciousness. Clearly, the human brain is sufficiently different from the brains of other animals to give us reasons for being very cautious about attributing consciousness beyond our species. As a result, the arguments that allow us to say with some degree of confidence that other humans have conscious states do not allow us to insert consciousness into the mental life of most other animals.

"My idea about consciousness in other animals is this. Consciousness is something that happened after the cortex expanded in mammals. It requires the capacity to relate several things at once (for example, the way a stimulus looks, memories of past experiences with that stimulus or related stimuli, a conception of the self as the experiencer). A brain that cannot form these relations, due to the absence of a cortical system that can put all of the information together at the same time, cannot be conscious. Consciousness, so defined, is undoubtedly present in humans. To the extent that other animals have the capacity to hold and manipulate information in a generalized mental workspace, they probably also have the potential capacity to be conscious. This formulation allows the possibility that some other mammals, especially (but not exclusively) some other primates, are conscious. However, in humans, the presence of natural language alters the brain significantly. Often we categorize and label our experiences in linguistic terms, and store the experiences in ways that can be accessed linguistically. Whatever consciousness exists outside of humans is likely to be very different from the kind of consciousness that we have.

"The bottom line is this. Human consciousness is the way it is because of the way our brain is. Other animals may also be conscious in their own special way due to the way their brains are. And still others are probably not conscious at all, again due to the kinds of brains they have. At the same time, though, consciousness is neither the prerequisite to nor the same thing as the capacity to think and reason. An animal can solve lots of problems without being overtly conscious of what it is doing and why it is doing it. Obviously, consciousness elevates thinking to a new level, but it isn't the same thing as thinking. [CS:TEB:301-302]

The argument from the uniqueness of the forebrain also shows up in pathological situations: "Deprived of the sense of personal integration and the "ownership' of his own mental activities, the person with frontal lobe damage inhabits a robotic world. It would not be an exaggeration to say he is deprived of his humanity, his identity as a member of the human community. Further, this deprivation progresses along a continuum. Although its beginnings are often subtle, progressive frontal lobe deterioration inevitably results in a sadly pathetic caricature of the human personality. Here is a description of advanced frontal lobe disease that captures the manifestations of the illness in its advanced stages: 'It is marked by personality change and breakdown in social behavior. Patients become unconcerned and lacking in initiative, and they neglect personal responsibilities, leading to mismanagement of domestic and financial affairs and impaired occupational performance. Medical referral may occur following demotion or dismissal from work. Affect is invariably shallow and emotional empathy with others is lost. Rigidity and inflexibility of thinking and impaired judgment are characteristic. Patients vary, however, with respect to certain behavioral features. Some patients present as overactive, restless, highly distractable, and overtly disinhibited. Their affect may appear fatuous and superficially jocular... Other patients present with apathy, inertia, aspontaneity, and emotional blunting.'

"...How curious and sobering it is to realize that our most advanced and evolved mental activities depend on unimpaired function of a specific part of the brain. Another way of putting it, our most human traits exist for us as a function of the human brain. Further, damage to our frontal areas could reduce any of us to an almost subhuman level of functioning, a kind of psychic limbo where we dwell in an eternal present, devoid of what I consider our most evolved mental ability: our capacity to empathize with others. No other creature, including the higher primates, comforts the injured or the bereaved, because other creatures cannot imaginatively identify with another. [CS:TMB:106-107, above]

(Tn: The issue of self-awareness is a bit more difficult to determine than just the mirror-criterion, IMO, and even strong pro-emotion writers agree with the lack of empathetic capability [e.g., PH:GN]. And, it should be noted that some primates do care for the sick, but this is normally, but not necessarily accurately, ascribed to learned behavior as opposed to sympathy.)

Although there are massive methodological problems with deciding this issue on the basis of observation and anecdotal data [e.g., NS:AAA] I personally tend to the side of the ethologists/naturalists here, that there is at least a spectrum of consciousness adequate to support a spectrum of suffering [e.g., PH:ATMS:49].

Now, I am not going to try to decide this issue here; for my argument I can agree that mammals can experience stress and suffering. But I also want to point out that IF they can experience suffering, THEN they also can experience pleasure during their lives. Cf:

"When electrodes are placed in some of these areas (limbic system), animals will show all the outer signs of rage. Stimulation in other areas arouses pleasurable response, indicated by the animals' enthusiasm to stimulate themselves over and over again by pressing a bar activating the stimulating electrode. Sometimes the animals activate what came to be called the 'pleasure center' as often as 7,000 self-stimulations an hour." [CS:TMB:143]

Indeed, the same endorphins that are used to mute pain, are known to produce a euphoria in humans when we exercise...If these operate the same in mammals (as the shared nervous system argument and similar neuropharmacological arguments run), then endorphins also would (logically) generate feelings of well-being in animals.

So, where does this leave us?

1. Out of 1.55M species, only 4,000 species (mammals) give us adequate reasons to SUSPECT the existence of a high-enough conscious level to believe they experience pain similarly to us. (And this is not accepted by all scientists, although our moral stances, relative to ethical treatment of animals, tends to err on the side of conservatism, as it should, IMO.)

2. In addition to the 4,000 species of mammals, we might add the 8.6K species of bird, but this is really stretching it.

3. This gives us only 14.6k species (out of 1.55M) that could experience 'agony' at all...a whopping 0.94%...(and consciousness would likely be on a spectrum, with primates being 'high' and birds being 'low')

So, the first issue of the 'all things live at the expense of an agonizing death of another' is clearly false...


The next part of the statement we want to look at is that of "death"--all things KILL what they prey on.

To what extent is this true?

This actually is a simpler and shorter question, because the types of predation are well-known.

(Note that we will not restrict our discussion here to the .94% of the species that could experience agony, but will look at all types of predation-like behavior.)

Let's first survey the situation "trophically", along the stages in the food chain/web...

Let's start with the terrestrial food "chain" (or more accurately, "web"):

1 . Obviously, those lowest on the food chain do not! The very bottom rung (the "producers") are the various plant species that produce energy from sunlight, or derive energy from dead organic matter ("decomposers"). Although some plants have predatory options (e.g., Venus flytrap eating flies, fungus eating nematodes), these are quite the exception. There are around 300,000 species of plants (nonvascular and vascular), compared to 1.2M species of animals. That is 20% of all known species that escapes from the "all kill" clause.

2. Then come the herbivores, which eat the primary producers (plants). There are two main groups here: the insects and the animals.

The insects (the dominant number of species in the world) do not generally kill the plant at all:
  "Occasionally, herbivory (insect) results in the death of mature plants." [X01:PAI:142] (emphasis mine)

"Negative effects of insect herbivores on mature plants, though palpable, are seldom fatal. Herbivory is more often life threatening for plants attacked at earlier developmental stages."[X01:PAI:143]

The animals do not generally 'kill' the plant either--they mostly fall into the "grazer" category:
  "Grazing can be regarded as a type of predation, but the food (prey) organism is not killed; only part of the prey is taken, leaving the remainder with the potential to regenerate" [NS:Ecol:115]

"Grazers also attack large numbers of prey, one after the other, during their lifetime, but they remove only a part of each prey individual rather than the whole. Their effect on a prey individual, although typically harmful, is rarely lethal in the short-term, and certainly never predictably lethal...[NS:Ecol:313f]

Oddly enough, grazing has been known to frequently increase plant growth and decrease plant mortality.
  "Often, there is compensatory regrowth of defoliated plants when buds that would otherwise remain dormant are stimulated to develop. There is also, commonly, a reduced subsequent death rate of surviving plant parts." [NS:Ecol:317]

Mammalian grazing has been known to increase plant production in the Serengeti by 2x [X01:PAI:166-168]

But the point should be clear--"predation" by herbivores does not "kill" the "prey".

3. Next come the carnivores, broadly speaking. This would include carnivorous insects and animals.

The vast majority of these would certainly kill their prey (although there are animal species that do grazing, such as fish that eat only the fins of larger fish).

Now, let's do the aquatic food web...

1. Primary producers (i.e., plants) in the oceans (for example). Since these are also photosynthetic, we have the same situation as in terrestrial situations.

2. Primary consumers are the herbivores, and these begin very, very, very small with the zooplankton. Because of the scale difference between land plants and sea plants, the herbivore base in the seas DO kill the consumed phytoplankton (by ingestion). [But, of course, the vast majority of macro-size sea plants that we are familiar with (e.g., sea weed) are not killed, similarly to land plants].

3. Carnivores of the sea also kill all that they prey upon, like land carnivores.

[The differences in the mortality of these tiny plants in these situations arise from the major differences in those ecological situations. The sea supports an abundance of much smaller life forms than does the land, largely due to the impact of gravity and the protein-vs-carbohydrate need differences of the dominant species in each. [X01:SLS:81-82].]

The second way we to slice this up, is by the types of predation...

Predators are typically divided into four categories:

1. True predators: These kill prey immediately, and usually consume much/most of the prey.

2. Grazers. As we have seen above, these do NOT kill their prey.

3. Parasites. This is a "relationship between two species of plants or animals in which one benefits at the expense of the other, without killing it" [EBE: s.v. "parasitism"]

"Parasites must also be distinguished from predators which, in general, kill their pray. Predators are normally thought to be larger than their prey...In fact there are many micropredators sometimes called parasitoids, which are smaller than their victim which they usually enter at the egg stage. The larvae of many hymenopteran and dipteran insects thus eat other developing insects from inside and invariably kill them. They are micropredators although the adult insects are free-living." [X01:AP:11]
4. Parasitoids. "One common type of parasite is the parasitoid, an insect whose larvae feed and develop within or on the bodies of other arthropods. Each parasitoid larva develops on a single individual and eventually kills that host. Most parasitoids are wasps, but some flies and a small number of beetles, moths, lacewings, and even one caddisfly species have evolved to be parasitoids." [EBE:s.v. "The Biosphere and Concepts of Ecology:Parasitism. [Actually, a few species only render the host sterile.]
  "Most parasitic insects are parasitic as larvae but not as adults, feed within or sometimes on their hosts, and eventually kill them. They are known as parasitoids. Approximately 10% of all insect species are parasitoids. Most, about 75%, of these are Hymenoptera; the remaining 25% are Diptera or Coleoptera." [NS:EOI:88]

(Notice, however, that the larva only kills one host in its lifetime--the adult does not 'prey' again itself, and sometimes never even eats again, depending on the reproductive cycle. Many spiders, as opposed to insects, do continue predation after development.)

So, we have two classes of predators that actually kill something (true predators, more than one individual; parasitoids, only one individual), and two that don't.

From the data above we can see:

1. Plant life (with minute exceptions such as carnivorous plants) does not kill any prey.

2. Land herbivores--insect and animal--do not generally kill their "prey" (i.e., plants)

3. Parasites do not kill their prey.

4. Parasitoids kill prey, but in a 'displacement function'. (One living individual displaces another individual, a net of zero-gain, zero-loss.)


Now, let's size this--how many species fall into categories 1-3 above, so we can see to what extent "all things kill their prey" is accurate.

1. How many plant species are there? 280,000.

2. How many land herbivores are there?

To calculate this we need to find out how many insects, amphibians, reptiles, birds, and mammals are herbivorous.
a. Insect: The insect orders each contain different 'mixes' of the various types of eating orientations:
  Scavengers (eating dead things) occur in 17 orders;
Carnivores (eating living things) occur in 16 orders;
Fungivores (eating fungi) occur in 6 orders;
Algae/Moss eaters occur in 3 orders;
Herbivores occur in 8 orders.

In the 8 orders containing herbivores, most of the species are herbivorous, and "over 50% of all insect species occur within the orders that contain herbivores" [above data from NS:EOI:8] (Also, many of the species that eat algae, moss, and fungi could be added to this list of non-killers.)

So, for insects, we get something around 50% representation, amounting to .5M species.

b. Amphibians: No numeric data was available to me at the time of writing, but recent literature points out that they are herbivorous as larvae -- mostly feeding on aquatic plants-- and carnivores as adults, largely consuming invertebrates.)

c. Reptiles: "today only a few herbivorous species remain. These include the marine iguana, which feeds on seaweeds, and some turtles and tortoises." [X01:PAI:164]

d. Birds: "many species of birds are herbivorous. " [X01:PAI:164]. The source didn't give any numbers, but using a conservative figure of 33% for the word "many", this would yield 1/3 of 8,700 species, or 2.8K species.

e. Mammals: "Roughly half of the nearly 4000 species of living mammals are primarily herbivorous. Of the 16 orders of terrestrial mammals, one is associated with plant nectar and pollen, two feed mainly on plant seeds, and seven consume mostly vegetative parts." [X01:PAI:163]

According to my desk calculator, this totals to around 1.28M, or 82% of all living "preying" forms that "do not kill their prey" (because they are herbivorous)...[and, if someone wants to argue that the plants don't actually have prey, we can back out the 280,000 plant species from the calculation and get a percentage of 78%]

So, the "all things live by the death of prey" position seems radically out of kilter with the known world.


Thirdly, we have to now ask the question about "all things" being "carnivorous" in the sense of active killing of animal life...we have to see how dependent life forms are on killing other life forms for food. We have already seen that the vast majority of living things (in terms of species, individuals, and biomass--by the way!) do not kill what they prey upon. But now we need to ask how many species do not "prey" or do not only eat animals that they kill. In other words, of those that eat things, how many of these live exclusively off killing their victims?

The energy-cycle has basically the following agents:

1. autotrophs: the plants and bacteria that create organic material (food) from the energy of the sun (i.e., photosynthesis), from chemosynthesis, or from thermal energy from undersea volcanoes.

2. heterotrophs: those that must "find" organic material to consume. There are 4 categories of these:

a. predators (which eat what they kill)
b. grazers (like predators, but which do not kill the source of organic material)
c. parasites (which get organic material from a host, without killing it)
d. decomposers (which get organic material from dead plants/animals)

Given this framework, what we need to ask are:

1. How many lifeforms are decomposers/scavengers (eating things already killed)

2. How many lifeforms are parasites (not killing was they prey upon)

3. To what extent do carnivores not always eat meat they actively kill (e.g., act as herbivores or scavengers)?

1. How many lifeforms are decomposers/scavengers (eating things already killed)?

There are essential two categories of these: (1) bacteria and fungi; and (2) detritivores (animal consumers of dead matter).

In the bacteria and fungi, we have at least [NS:Ecol:406]:

a. Phycomycetes (a mixed group of at least 3,000 species [NS:DLO:chapter 3])
b. Fungi Imperfecti (15,000 species [NS:DLO:122])
c. Basidiomycetes (22,250 species [NS:DLO:115])
d. Actinomycetes (less than 10,000)
e. Ascomycetes (32,300 species [NS:DLO:122])
f. Lactobacilli (100-500?)
g. tons of specialist forms, which appear after the 'generalists' above do their work


In the detritivores, we have at least [NS:Ecol:408, most specie counts are from NS:DLO or EBE]:

a. Nematoda (most of 20,000 species)
b. Protozoa (various)
c. Rotifera (1,800 species)
d. Acari (mites and ticks, 400+ families)
e. Collembola (3,500 species)
f. Protura (150 species)
g. Diplura (3,100 species, apterygotes)
h. Symphyla (120 species)
i. Enchytraeidae (no data)
j. Chelonethi
k. Isoptera (2,000 species)
l. Opiliones (3,400 species)
m. Isopoda (4,600 species)
n. Amphipoda (6,200 species)
o. Chilopoda (2,800 species)
p. Diplopoda (10,000 species)
q. Megadrili [e.g., earthworms] (3,200)
r. Coleoptera (4 families of over 42,000 species)
s. Araneida (less than 5,000 species)
t. Mollusca (at least 25,000 species within this group would be decomposers)
u. "hagfishes are mostly saprophagous, feeding as scavengers." [X01:BFCB:430]
v. To this list we could add the various species of vultures and other main-line carrion

If one also notes that scavengers are present in more orders (i.e., 18 [NS:EOI:8]) of insects than any other 'dietary preference' (e.g., carnivore, herbivore), then we can easily assume that the 213K species listed above would increase to 300k --easily more that the number of species that "kill their food" (approx: 280k).

2. How many lifeforms are parasites (not killing was they prey upon)

"Parasitism is thought to be the most common way of life, and parasitic organisms may account for as many as half of all living species. Examples include pathogenic fungi and bacteria, plants that tap into the stems or roots of other plants, insects that as larvae feed on a single plant, and parasitic wasps. [EBE: s.v. "The Biosphere and Concepts of Ecology:Parasitism"].
(And, much, if not most, parasitism is virtually unnoticed by the host, or in many cases, helpful or even necessary.)
  "Wood-eating insects and herbivorous mammals that are essentially cellulose feeders harbor in their guts an abundance of protozoan, bacteria and yeasts and these organisms are able to digest cellulose or to manufacture amino acids. When experimentally deprived of these organism they waste away, despite the fact that they continue to feed, because they lack the necessary enzymes to degrade cellulose." [X01:AP:8]

"The okapi, which lives in the tropical forests of central Africa, harbours at least five kinds of worms simultaneously and some of these may be present in numbers of several hundreds. The host does not seem any the worse for this and can feed itself as well as cater for the fauna it contains." [X01:AP:10]

"It appears that many plants and animals may tolerate 'parasites' without showing any harmful consequences..." [NS:Ecol:457]

So, if I add the 300K species from #1 above (20% of all living species) to the 50% parasite group, I get more than 2/3rd of all species (and massively more individuals!) of all predators do NOT kill the prey they prey upon...


3. To what extent do carnivores not always eat meat they actively kill (e.g., act as herbivores or scavengers)?

What is interesting here is that even the "spectacular" carnivores still manifest levels of omnivorous behavior at various levels of intensity, and also manifest considerable scavenger behavior:

"It does not, however, follow that because their basic adaptations relate to predation, all Carnivora live on flesh alone. Although many species live mainly on flesh, I do not believe that we know enough to state that there is any member of the order that never partakes of vegetable food: for many species plant foods make an important contribution to the diet and there are even a few that have become secondarily almost pure vegetarians." (for example, bears: "extremely omnivorous and, despite their large size, they feed largely on fruit, nuts, tubers, and insects and do not very often kill prey of any size.") [NS:TC:2-3]

"Most species of fishes are predatory, feeding on live animals or parts thereof. But in some habitats, especially in the tropics, 10 to 20 percent of the species present and nearly half of the individuals may depend primarily on plant material for food; and in ocean areas and lakes where soft bottom materials accumulate, there may be detritus feeders...Although we may tend to consider some species as mainly carnivores or herbivores for the purposes of some discussions, they may often tend toward omnivory." [X01:BFCB:429]

"The large decomposers (in the Serengeti) include lions, leopards, hyenas, wild dogs, and jackals, all of which will scavenge and thus act as decomposers at least part of the time. While there is relatively little competition for living prey among these large carnivores, competition for dead prey is another story. Hyenas get about a third of their food that way, lions 10 to 15 percent, leopards 10 to 15 percent, and hunting dogs 3 percent. Lions are the only predators not significantly interfered with by others. But cheetahs, which alone among large Serengeti predators do not add to their diets by scavenging, lose 10 to 12 percent of their prey to hyenas and (occasionally) lions; hunting dogs lose about half their kills to hyenas; and hyenas and leopards are thought to lose 5 percent or more to lions." [X01:MON:252]

But: "Indeed, in Ngorongoro, the traditional relationship between lions and hyaenas was reversed and the lions got most of their food from kills made by the crocutas." [NS:TC:203]

"A second form of adaptability shown by the large predators relates to the sources of food. The majority of large carnivores are prepared to take any food they can get and very few are finicky about whether the meat is fresh or not. Most of them will feed on a carcase, whether it be of an animal that died naturally or the remains of some other predator's kill, and, if superiority in size or in numbers permits, most are prepared to drive the rightful owners off a kill and appropriate it...the is no clear and simple division into true predators and obligate scavengers: the traditional 'scavengers' also kill for themselves and the predators scavenge off each other's kills and even appropriate those of the 'scavengers', whenever the chance arises...widespread tendencies to scavenging and kill-thieving of the modern carnivores" [NS:TC:223-224]

"(In temperate zones) Of small carcasses--of such a size that they may be removed in their entirety by a single scavenger, it has been calculated that crows, foxes, and badgers may take between 75% and 100%, depending on the season...It has been shown that vertebrate scavengers in temperate systems will find all small carcasses within thirty days or so of death." [X01:CDDAW:7]

"But few of the vertebrates found as scavengers feed exclusively on carrion. Most vertebrate scavengers are normally recognized as predators--but are not above accepting carrion should they chance upon it." [X01:CDDAW:30]

"Numerous species of fish, free-swimming molluscs (like squids and octopuses), swimming crustaceans (such as lobsters or shrimps and prawns) feed upon the carrion as it sinks (just as vertebrate scavengers feed on terrestrial carrion)." [X01:CDDAW:58]

"White sharks have been seen feeding on dead whales, but it is unlikely that even the largest individual would be able to kill a large whale on its own, and there is no evidence that they ever hunt cooperatively...Whale carcasses, both floating and submerged, may provide an important food source for white sharks, especially outside of the pinniped breeding season when this resource is unavailable to them." [NS:RAL:69]

"Most members of the order (tn: Carnivora) are in fact meat eaters, although some ursids [tn: bears], procyonids [tn: raccoons and pandas], and canids rely heavily on vegetation, and the giant panda (Ailuropoda melanoleuca) lives almost entirely on bamboo shoots. " [EBE: s.v. "carnivore"]

"Cannibalism (among lions) also occurs, and the corpse of any conspecific killed in a fight is often treated as food: Schaller saw a lioness eating one of her own cubs, killed by a marauding male belong to another pride. The lion has no aversion to carrion and will stay with a kill until it is finished, even if by then it is far from fresh...The lions' habit of appropriating the kills of crocutas has already been mentioned and they will sometimes dispossess a leopard. Lions will also now and then take small prey such as rodents and tortoises and, as rivers dry up, will hook out fish trapped in shallow pools: they will also eat termites when a flight makes them easily available in large numbers and grass and various fruits are eaten now and then." [NS:TC:205f]

"Many of the predatory raptors will also take carrion when the opportunity arises. These include many of the eagles, such as the golden eagle and the bald eagle, birds we usually think of as exclusively predatory." [NS:RAL:124f]

"They (the larger predators) are really to be looked upon as scavengers without the patience to wait for their meat to die. They cheat the bacteria who would have got the bodies otherwise." [X01:WBFAR:156]

So, what does this aspect of the question reveal?

a. There are more species that eat materials killed by others than species that kill for themselves;

b. There are many more species (by a factor of 10) that derive life from a host without killing it;

c. Even the most vivid and effective of killers often eat what they did not kill.

Therefore, not ALL things live off (directly) the "agonizing death of a feeling, breathing life".

So, the original statement of "ALL", "DEATH", and "AGONIZING" seems way off base:


It would thus seem that the practice of painful predation is not so ubiquitous at all, and actually constitutes a very minute fraction of the experience of life on earth.


But let's continue to "size" this problem...

1. We have been talking about species so far, but how many actual individuals are involved in painful predation?

This basically can be analyzed under two-concepts: the food-pyramid and energy/ecological efficiency of tropic levels.

The food-pyramid concept is essentially "demographic"--you count the biomass of plants, herbivores, secondary consumers (carnivores), tertiary consumers (super-carnivores) per area and see what the ratios are. Consider the food pyramid of a representative bluegrass field [NS:BPS:134]:


3 Tertiary Consumers
350,000 Secondary Consumers
700,000 Primary Consumers (herbivores)
6,000,000 Producers (plants)

"The total mass of the animals at the top of the food pyramid, the secondary carnivores, is less than the total mass of the animals close to the plant source of food, the herbivores, because these is less energy available to the secondary carnivores. An individual secondary carnivore is usually very large. Large body size is useful to these animals, since it enables them to capture and kill their prey. However, the number of such carnivores is small."

Part of this is related to the "quantum levels" of body size, as well.

"A typical patch of woodland in any of the temperate lands of the North will contain a host of insects and then nothing larger running about until we get to the size of small birds, which are much less numerous. Another size jump brings us to foxes, hawks, and owls, of which there may be only one or two. A fox is ten times the size of a song bird, which is ten times the size of an insect. If the insect is one of the predacious ground beetles of the forest floor, which hunt among the leaves like the wolf-spiders, then it, in turn, is ten times bigger than the mites and other tiny things that they both hunt."

"In the wood as elsewhere there are distinctly different sizes, and the little ones are the most common. The same sort of things exists in the sea in even odder form, for in the open sea the really tiny things are plants; the microscopic diatoms and other algae. Ten times bigger than these (give or take a few times) are the animals of the plankton, the copepods and the like. Bigger still are the shrimps and fish that hunt those copepods. Then another jump brings us to herrings, then to sharks, or killer whales. In any one place in the sea, this clumping of like into different sizes is the normal thing.

"In the sea the rarity of the large is also most clearly shown. Great white sharks are extremely rare, and the other kinds of shark are scattered pretty thinly over the seas too. Fish of the herring size are vastly more common than sharks, but, even so, the number that are seen in a casual dive in the sea is seldom immense....The tiny things of woodland and sea are immensely common; bigger things are a whole jump bigger and a whole jump less common; and so on until we reach the largest and rarest animals of all. A like pattern can be found in tropical forests, Irish bogs, or just about anywhere else. It is an extraordinary thing but true that life comes in size-fractions which, for all the blending and exceptions that can be found by careful scrutiny, are remarkably distinct. Animals in the larger sizes are comparatively rare.

"With every jump in size an even mightier loss occurs in numbers"

"All the insects in a woodlot weight many times as much as all the birds; and all the songbirds, squirrels, and mice combined weight vastly more than all the foxes, hawks, and owls combined." [X01:WBFAR:18-19,23,24]

Let's do a quick calculation for our 3 tertiary carnivore biomass-units above. These three units (of foxes, let's say), will each likely eat somewhere around 40 times their bodyweight in a year (12x for male lions, 20x for lionesses, 50x for raptors, 250x for shrews--the smaller the animal, the faster the metabolism, the more it must eat). If they are ten times the size of the prey, that means that they each have to eat (whether they killed it or not) 400 prey biomass units (small mammals/birds) during a year. This number would be smaller, of course, if they substituted insects and plants for some of the calorie requirements (which they routinely do). For the three of them, that represents only 1,200 prey biomass units (or approximately 8 per week per fox-unit) out of a population base of 350,000 biomass units. (No wonder vertebrate predators are of no consequence in controlling the population of prey below them--they just aren't enough of them, and they just don't eat enough!)


The food-pyramid is such, because the ecological efficiency ratios are what they are. The concept and implications for the number of super-carnivores are clear:

"The ultimate furnace of life is the sun, streaming down calories of heat with never-fainting ray. On every usable scrap of the earth's surface a plant is staked out to catch the light, its green array of energy receptors and transducers tuned and directed to the glowing source like the gold-plated cells on the arms of a satellite. In those green transducers we call leaves, the plants synthesize fuel, taking a constant allotment of the streaming energy of the sun. Some of this fuel they use to build their bodies, but some they burn to do the work of living. Animals eat those plants, but they do not get all the plant tissue, as we know because the earth is carpeted brown with rotting debris that has not been part of an animal's dinner. Nor can the animals ever get the fuel the plants have already burned. So there cannot be as much animal flesh on the earth as there is plant flesh. It is possible for large plants to be vastly abundant and ranked side by side, but animals of the same size would have to be thinly spread out because they can only be a tenth as abundant.

"This would be true even if all animals were vegetarian. But they are not. For flesh eaters, the largest possible supply of food calories they can obtain is a fraction of the bodies of their plant-eating prey, and they must use this fraction both to make bodies and as a fuel supply. Moreover their bodies must be the big active bodies that let them hunt for a living. If one is higher still on the food chain, an eater of a flesh-eater's flesh, one has yet a smaller fraction to support even bigger and fiercer bodies. Which is why large fierce animals are so astonishingly (or pleasingly?) rare." [X01:WBFAR:26-27]

and these 'caloric transfer rates' (ecological efficiency) are quite small:

"Daphnia can convert about 10 per cent of the plant food that they digest into increased Daphnia production, which can be harvested without harming the future production of new Daphnia. Slobodkin also summarizes many less precise measurements that have been made in natural populations with real carnivores, who eat their harvest of herbivores. This is remarkable, because it looks as if carnivores really do harvest their herbivore prey at the maximum prudent rate, in spite of the fact that we might expect the selfish process of natural selection to lead to overexploitation of prey with resulting reduction of yield. This is remarkable also because the estimates are quite uniform, suggesting that ecological efficiency is about 10 per cent, whether the herbivore is a Daphnia or a cow."

"There are four stages in this food chain: plants, herbivores, carnivores, and secondary carnivores. Each stage can expect to take in energy at about 1/10 the rate of the previous stage; hence the secondary carnivores are reduced to roughly 1/10 X 1/10 X 1/10 = 1/1000 of the energy taken in by the plants. Supercarnivores which ate these would be reduced to 1/10th of this or 1/10,000 of what the plants received, and so on. No wonder that every few species find it worthwhile to be such a supercarnivore--there is practically no energy available to them!" [X01:BP:178]

Just to 'dramatically' point out that the non-feeling life forms on the plant vastly dwarf any creatures that could possibly 'feel' agony in being killed, consider:

1. In a gallon of seawater, there are between 1 and 2 million diatoms. [NS:BPS:196]

2. "For example, beneath a square yard of Danish pasture, 10 million roundworms, 45,000 small relatives of earthworms, and 48,000 minute insects and mites were counted." [X01:MON:37]

3. "A census of 1/30 of an ounce of soil from a fertile farm has turned up 30,000 protozoa, 50,000 algae, 400,000 fungi, and more than 2.5 million bacteria." [X01:MON:37]

4. One milliliter of sheep dung may contain: 10**11 bacteria (a hundred billion!), 10**6 fungal mycelia, and 10**10 actinomycetales. [X01:CDDAW:45]

The relevance of this topic to our topic of suffering should be clear: any possible conscious suffering is more likely to occur higher up on the pyramid, when the numbers of actual individuals being killed will be minute to that below it.

In other words, the more numerous and frequent are the deaths that occur per unit time, the less likely there is ANY 'suffering' at all.

2. "But what about those 'big fish eating the smaller fish eating the tiny fish'--wouldn't that indicate huge amounts of suffering?

Actually, no.

a. We have already seen that the fish do not experience 'agony'.

b. Most fish do NOT eat other fish, but eat the unquestionably non-agony life forms "below" it:

"The benthic (tn: ocean floor) invertebrate fauna provides a significant portion of the food for carnivorous fishes. For the most part, organisms such as aquatic insects (including larvae and pupae, small crustaceans, molluscs, and worms) constitute the main food source of most of the fishes." [X01:BFCB:429]

c. Even in the cases of fish eating other fish, these involve actually much less 'struggle' than one would find on the African plain. Most of it is instantaneous, and over in less than a minute (before the physiological system of the prey fish has time to crank up the visceral 'feeling' hormones, as we saw above).

"It has been found that the methods of predators are numerous. Not all are bloody and dramatic. Many involve only instantaneous, silent gulping." [X01:TP:11]

"Because the majority of fishes engulf and swallow their prey whole, they are not known for complex handling procedures." [X01:FPvol8:100]

"For example, when fish eat insects or small aquatic organisms the prey is generally captured and swallowed whole..." [X01:EBF:77]

and when they do have to chew it is quick and specialized, with specific teeth that chew as they swallow...
  "Relatively well-developed pharyngeal teeth are also found in a number of omnivorous and herbivorous fish species, with the form of the teeth being related to the composition of the diet. Many plants have tough cellulose cell walls which must be broken down before the organic cell contents can be released." [X01:EBF:83]

"Although food is collected by the mouth and is sometimes dealt with by the jaws and their teeth, the real processing, in some cases amounting to mastication, usually takes place in the throat or pharynx where flattened pharyngeal bones at the back of the throat is such that all food must pass between them 'as between a pair of millstones'. The number, size, and structure of teeth planted on the surface of these bones differ according to the type of food most commonly processed." [X01:FPvol8:94] Some fishes even have teeth in the esophagus. [X01:FPvol8:166]

It is interesting to note that the physiological systems of fish would actually 'calm the fish down' when engulfed:
  "Roberts reviewed the work of several authors which showed that almost any disturbance or rapid environmental change will slow or inhibit the heartbeat, a phenomenon known as bradycardia." [X01:CBF:241]

d. Strangely enough, the amount/frequency of predation (per unit of biomass) among fish is considerably less than that of terrestrial mammals.

The reason for this has to do with the 'cold-blooded' nature of fishes (as well as reptiles and amphibians, by the way). They simply do not need as much food as land-based mammals.

"Warm-blooded animal (birds and mammals) have basal metabolic rates about five to ten times higher than those of similarly sized cold-blooded ones (reptiles, amphibians, fishes)." [NS:RAL:39f]

"But its (a pet crocodile) low metabolic rates mean that it requires far less food, which is an advantage. I used to feed the caiman a tiny piece of liver once a week, whereas the family cat demanded three meals every day." [NS:RAL:40]

"Once the crocodile has gorged itself on wildebeest, it will go without food for several weeks. In contrast, a similar meal eaten by a lion would last only for a few days. Like other reptiles, crocodiles eat about two or three times their body mass in a year, compared with about twenty times for a lioness." [NS:RAL:44]

"A snake's food requirements are therefore modest, and it consumes only two or three times its body mass in a year." [NS:RAL:52].

"It has been estimated that an adult [Komodo dragon] consumes between three and four times its body mass per year, compared with about thirteen for a male lion and twenty for a lioness." [NS:RAL:55]

"From the body temperature data obtained from the white shark, the researchers estimated that it had a low metabolic rate, and that a single meal would last an individual for more than a month. This certainly makes good sense, and we should dismiss the notion that sharks are forever on the prowl for something to eat." [NS:RAL:71]

3. "But what about Mill's statement--aren't animals constantly chasing, tormenting, and killing prey?"

Actually, no. (Even after you filter out the gross anthropomorphism in the 'tormenting' word!)

a. If you look at the lives of representative 'spectacular' predators, you find that they don't spend all their time hunting food at all.
  "A wild dog's life is not a bad one. The dogs are rarely active for more than four or five hours a day, when they hunt and feed, the remainder of their time being spent at leisure...they are the most formidable killers on the African plains..." [NS:RAL:18]

Lions do most of their hunting at night. [NS:RAL:11] and most prey suffice for more than one meal [NS:TC:224]

"From the body temperature data obtained from the white shark, the researchers estimated that it had a low metabolic rate, and that a single meal would last an individual for more than a month. This certainly makes good sense, and we should dismiss the notion that sharks are forever on the prowl for something to eat." [NS:RAL:71]

"Such snakes, like pythons, may go for two or three months without feeding..." [NS:RAL:53]

"Crocodiles spend half their time in the water, seldom straying far from the water's edge. Most of their days are spent basking in the sun or lying in the shade..." [NS:RAL:42]

"If the spider is that successful, it will probably not hunt again for many more days, because spiders have low metabolic rates and correspondingly low food requirements...Spiders have been known to live for over six months without eating." [NS:RAL:160]

b. Predators are not even successful, most of the time!
  "Lions, like most other predators, are by no means successful every time they hunt, losing more potential prey than they ever catch." [NS:RAL:17]

"The hunting successes of the lion, averaged for all hunts both day and night, varied from 14 percent for reedbuck to 32 percent for wildebeest, so the odds are well in favor of the prey. Hunting dogs and cheetahs did considerably better, with average successes for all prey hunted of 70 percent." [NS:RAL:34]

"Mech also gives the details of the hunting [by wolves] of caribou and mountain sheep. In all cases it appears that the success rate of the wolves is low: many attempts fail for every one that succeeds." [NS:TC:148f]

"Kruuk summarized the results of his extensive observations of hyenas hunting wildebeest calves both individually and in groups. Only about one third of 108 attempts by one or more hyenas to capture calves were successful." [CS:AM:63]

Of a major study done on wolves/moose predation in Isle Royale National Park, wolves only had a 5% success rate, in 120 active pursuits. [NS:TC:148] and in some cases, this has resulted in starvation for wolves [NS:TC:144].

Peregrines have a success rate in the 10-30% range, and falcons around 11% [NS:RAL:111-113]

c. Most healthy individuals in a species are NOT the targets of predators, contrary to popular opinion.

"He found that the muskrats capable of holding a territory in the most favourable parts of the habitat were virtually immune from predation but that mink and fox levied a heavy toll on the homeless, the transients, the weaker animals forced out to live in sub-optimal habitats and on those suffering from disease or from wounds received in territorial fights with their fellows." [NS:TC:149]

"Kruuk observed that predators whose home area was close to that of territorial tommies never hunted these familiar neighbors. Some hyenas usually rested from midday until late afternoon in dens located within territories of male tommies. When they left their dens in the early evening they were presumably hungry; but, although they were often surrounded by tommies, they passed between them and hunted in other areas. Perhaps the hyenas knew that the local tommies were alert and difficult to catch." [CS:AM:59]

"Mech also gives the details of the hunting [by wolves] of caribou and mountain sheep. In all cases it appears that the success rate of the wolves is low: many attempts fail for every one that succeeds. If this is so, it seems a priori likely that the individuals killed are not a random sample of the prey population but are mainly animals that are in some way inferior to or at a disadvantage as compared with their fellows. Studies of the kills made bear this out: they consist mainly of the young and the aged and those killed as young adults are often injured or diseased." [NS:TC:148f]

"The natural predator is not a random killer, nor does he choose trophy specimens: his selection, based on what he can most easily get, is comparable with that of the stock breeder who eliminates weaklings from his breeding herd..." [NS:TC:149]

"Usually they [the big cats] feed by culling the old, the sick, and the young." [X01:WBFAR:156]

(I might point out that the "young" are NOT their preferred target, in most cases, compared to the old and sick. The predator is trying to maximize the food, while minimizing the effort. One kill that takes down a full-grown prey, is MUCH less "expensive" that two or three kills of youth. This is borne out by the data of their (in this case, lions) actual eating habits: "the preferred prey is medium-sized ungulates" [NS:TC:205].

d. In fact, the data suggests that, for the vast majority of a prey animal's lifetime, the predator/prey interactions are not "anxiety producing" at all:

"Potential prey animals are almost constantly on the watch for dangerous predators, and once one appears they keep it under close observation. Only on rather rare occasions does the predator become serious about attacking, and only then, ordinarily, do the prey animals become seriously alarmed. When predators and prey can see each other, they spend most of their time monitoring each other rather than in attacking or fleeing...

"When Thompson's gazelles detect a predator, they often do not flee but move closer. They appear to be much interested and to be inspecting the dangerous creature. Walther sometimes saw a herd of tommies recognize a predator at 500 to 800 meters and then approach within 100 to 200 meters. Under these circumstances the herd contracted into a smaller area than when feeding, the individuals remaining closer to one another. When the predator moved, the herd followed it, evidently aware of the danger and ready to dash off at the first sign of an actual attack. The predators also seem to understand the situation and rarely attack a group of alert tommies. Predator monitoring by territorial males was especially evident. At the approach of a predator in daytime the females generally moved away, while the buck stayed in his territory and kept the predator under close watch. As it moved he usually followed at a safe distance until it reached the territorial boundary. Then one of the neighboring territorial males would take over the monitoring of the dangerous intruder. This sort of predator monitoring was so effective that predators captured only one of fifty territorial males that Walther studied intensively during a two-year period.

"George Schaller (1972) describes other examples of prey animals monitoring the behavior of predators and not appearing to be frightened unless the predator rushes at them directly. When a lion is walking along steadily, tommies, zebras, wildebeest, and other potential prey usually face the danger in an erect posture but do not run away. Wildebeest usually keep up an incessant grunting, but when a lion approaches they stop, so that the predator is surrounded by a zone of silence, which undoubtedly warns others of the danger. A group of wildebeest may even approach a predator and line up to watch it pass. But if a lion stops and turns in their direction, the grazing animals usually flee for a short distance, then turn and stand watching again. Roughly thirty meters from a lion seems to be considered a safe distance in open country, but when potential prey animals move into thick vegetation they behave much more cautiously. " [CS:AM:57f]

"The most abundant antelopes of East Africa are the Thompson's gazelles, or tommies, which are preyed upon by many carnivores, including leopards, lions, cheetahs, hyenas, and wild dogs...Despite the fact that tommies are an important portion of the diet of several predators, they do not appear to spend their lives in a constant state of terror...Walther states that tommies seem less disturbed by predators at a reasonable distance than by heavy rainstorms." [CS:AM:54]

e. The above data (plus our understanding of ecological niches and mathematical biology) leads to a more balanced view of the co-existence of predator and prey:
  "All the exciting list of animals in the great herds can be seen by an ecologist in terms of the exclusion principle: a set of species which represents a set of niches, each one of which is a way of life conditioned to avoid competition with the other ways of life around it...Peaceful coexistence, not struggle, is the rule in our Darwinian world. A perfectly fashioned individual of a Darwinian species is programmed for a specialized life to be spent for the most part safe from competition with neighbors of other kinds. Natural selection is harsh only to the deviant aggressor who seeks to poach on the niche of another. The peaceful coexistence between the species, which results from evolution by natural selection, has to be understood as an important fact in the workings of the great ecosystems around us." [X01:WBFAR:149]

"There is no doubt that all these big fierce predators have some effect on the numbers of their prey because they kill the young. But they cannot usually kill a very large proportion of the young because the number of predators is relatively small. The young typically make their appearance at only one time of the year, and the predators must live the rest of it too. The numbers of big cats and wolves that a herbivore mother must look out for in the spring is mercifully low because it will be the number that has been kept alive through the winter by the supply of old and sick animals. It thus seems very likely that the larger and fiercer predators are not nearly so important in regulating the numbers of animals in nature as common sense suggests. They are really to be looked upon as scavengers without the patience to wait for their meat to die. They cheat the bacteria who would have got the bodies otherwise. Two rather pleasing thoughts come from this discovery. One is that the lives of big game animals are lived in a large measure of freedom from the awful world of tooth and claw that we can conjure up by a careless reading of Darwin. Not only do these animals live in that peaceful coexistence with their neighbors, which the mathematical ecologists discovered, but they also may live with less fear of being killed than we had supposed, except as a sort of euthanasia. The second pleasing thought is that those who like to shoot big game themselves no longer have a pretext for killing off the wolves and--cats before they start on the deer." [X01:WBFAR:156]

4. "But still, the predators inflict an agonizing death on the prey, at least in the minute fraction you delineated above..."

Well, let's try to see the factors, facts, and the context of this...

a. There are a couple of powerful factors (other than hunger!) that 'encourage' predators to kill their prey as quickly as possible (i.e., with as short a period of pain, and intensity of pain, as possible)
1. The ecological concept of 'handling cost' of prey capture points out that the predator must minimize the exertion required to capture/consume the prey. The whole point of 'preying' was to replenish lost calories; a long-drawn out period of chase, capture, followed by a long period of energetic "killing" would cost many more calories than most predators are willing to expend. They are conservative in this area, and they try to reduce their high-energy capture and handling times/costs as far as possible. This argues for a very swift death event for the prey.

2. The need to "not draw attention" to the event. Except in the case of the lion (and maybe the largest marine predators), a "struggle" replete with cries of prey and noises of movement, virtually "invites" other predators to the scene! It is in the interests of all "sub-lion" predators to dispatch the prey with the minimum struggle (i.e., a quick death) and with the minimum pain (i.e., no loud screams or cries).

3. The need to avoid injury. Predator-prey interactions in the large-size mammalian world is not a 'sure thing' for the predator. Wolves that attack moose and lions that attack wildebeest are always at risk of getting injured by the prey in the confrontation. This applies to group hunts as well as solitary hunts. A wounded lion or wolf will not be able to hunt successfully and so will starve. This tends to make the predator pick on the easiest prey (sick, old, young, inexperienced) and to neutralize their ability to hurt them (via a retaliatory bite or hoof-kick) by a quick kill.

b. The facts of how death occurs for much/most prey is predictable from the above factors:
  1. the vast majority (but by no means all--the group hunts of large game by wild dogs and whale hunts by killer whales are obvious exceptions) of terrestrial Carnivora kills will be by asphyxiation (5-8 minutes) for larger prey, or the spinal "death bite" (instantaneous) for small-to-medium prey. Asphyxiation will result in loss of all consciousness even before death occurs.

The canine "death bite" is the dominant method for the vast majority of canine kills all over the world. It is used for the vast majority of smaller cats worldwide, and used by the big cats whenever possible as well. It is noted among researchers for its "humane" character:

"The killing bite is aimed accurately at the constriction just behind the head and death is normally the results of a canine tooth passing between two vertebrae, forcing them apart and breaking the spinal cord. One of Leyhausen's blackfooted cats was such an adept at this technique that when it was necessary to slaughter a number of guinea pigs to store in the deep freeze for future use, the simplest and most humane way of killing them was to enlist his help." [NS:TC:217]
Other mammalian predators, such as wolverines and weasels, use a similar neck/head bite [NS:TC:177f], as do many predatory birds [NS:RAL:chapter 5], and some carnivores use shaking to break the neck [NS:TC:197]. Other birds use talons to piece the skull, resulting in instantaneous death [ NS:RAL:chapter 5]. All of these are instantaneous or virtually instantaneous deaths, with an absolute minimization of pain.

The main exception to this 'neural-based' death (among the mammalian predators) is with the canids. The wild dogs and hyenas (when hunting prey larger than themselves and in a group; they use the neck-breaking shake on smaller prey) use the method of rapid disembowelment. One work describes this [X01:IK:13-14}:

"Since that night we have seen the same gory drama enacted time and time again, for Cape hunting dogs, commonly known as wild dogs, and jackals also kill by this method of rapid disembowelment. We still hate to watch it and yet, though it seems longer at the time, the victim is usually dead within a couple of minutes and undoubtedly in such a severe state of shock that it cannot feel much pain. Indeed, lions, leopards, and cheetahs, which have the reputation of being 'clean killers', often take ten minutes or more to suffocate their victims..." [The authors go on to cite parallels from wartime and traffic accidents, in which the pain 'felt' by the sufferer is less the more severe the injury, due to the "anesthesia" effects of deep shock.]

2. Specialized forms of killing (outside the mammals) generally involve poisons/venoms (such as snakes, cone snails, spiders/parasitoids). Most of these poisons affect some major internal system of the prey (e.g. respiratory, cardiac, muscular) but they invariably also affect nervous system transmission. In other words, they shut the 'feeling' system down, along with whatever other system they are targeting. This minimizes sensation during the death process (for the reasons of the factors above).

These are so effective on nervous systems that humans use derivatives of these for pain-treatment.

"We still lack definite answers to such questions as to whether the intoxication mechanism of snake venoms results from decisive or insignificant, primary or secondary effects on the CNS." [X01:BRvol8:475]

Cobra venom was analgesic in mice, guinea pigs, cats, rabbits. [X01:Brvol8:475]

"Several preparations of cobra venom and other snake venoms are being used in medicine for the treatment of severe pain." [X01:BRvol8:475]

Injection of snake venoms into dogs and monkeys produce electroencephalographic silence within one minute...and "Investigations on conscious rabbits lead to the conclusion that cobra venom contains components acting on cortical and subcortical areas affecting cortical arousal response." ...but some simply shut the spinal cord down (as in cats)...they pass the blood-brain barrier very slowly, so the effect is likely on the spinal cord [X01:BRvol8:476,479]

Cone snails produce a conotoxin that is used commercially for chronic pain relief (SNX-111, ziconotide, a product of Neurex Corporation)

The parasitoids (mentioned by one of the questioners) actually don't even need the anesthetic properties of their poison (they use it simply to reduce the possibility of escape or egg damage). In the cases of spiders and insect parasitoids, the host insect doesn't have a sensation of their abdomen anyway! We noted above the dragonfly that ate his own abdomen, and the evidence for no 'pain' processing in insects. To this we can point out that some parasitoids do NOT paralyze the hosts of their eggs, but let them run around free, not showing ANY deleterious effects of the 'alien within':
  "The females of the superfamily Ichneumonoidea deposit their eggs in or on the larvae or pupae (rarely eggs or adults) of the host species; the legless, maggot-like larvae that hatch from these eggs feed on the body fats and fluids of the host until fully grown. At this time, the larvae usually spin silken cocoons, within which they pupate and from which the adult parasites eventually emerge. Those species parasitizing exposed hosts usually develop as internal parasites; those attacking hosts concealed in wood burrows, plant stems, cocoons, or leaf mines feed externally. In the case of internal parasites, the hosts feed and behave normally until shortly before the parasitic larvae have completed their development; the hosts of the external feeders are paralyzed by the female parasites. In most cases, one parasitic larva completes its development within or upon its host; in some species, however, many larvae develop in one host. [EBE: s.v. "Insects:Life cycle.:Solitary forms."]
For the paralyzed hosts, we have an additional reason to believe that they feel nothing: the effects of the paralyzing venom (one scientist likened the state to "suspended animation" NS:RAL:163]).

For example, take this account of the Ichneumon (in the question), given in NS:RAL:235:

"The hitchhiker is an ichneumon wasp and is in the act of depositing her eggs inside the caterpillar's body. When the eggs hatch, they will live inside the caterpillar, feeding on its tissues and growing as the caterpillar grows. The unwilling host will be little affected by their brooding presence, but when it is time to change into a butterfly, the larvae will erupt from its body, so killing it."

Notice that the host is oblivious to the 'alien' and continues to grow and is only at the rupture of the exoskeleton that the host finally dies. No indication of suffering by the host in the least--indeed, indications that it simply 'goes about its business'.

(There are non-chemical versions of this as well: "Some predators are aided in food capture by strong electric organs that stun or immobilize prey." [X01:BFCB:429] )

3. In aquatic settings, most of the predation (of reasonably higher forms) is by simple gulp/swallow. This would result in an instantaneous death (if the various teeth structures were used in swallowing) or in asphyxiation (3-6 minutes) for the smaller fish forms (remember from the discussion above, their internal responses of stress would not kick in within this time frame, and the slowing of the heart rate would move them closer to a suspended animation status).

4. In aquatic settings, the really high-end killing (e.g., white sharks, killer whales) is much more bloody (since asphyxiation is rarely an option), but it is rapid and much more infrequent as well (as we noted above). With the exception of when killer whales attack a large whale as a group (similar to big cats attacking an elephant), most attacks on animals result in death very, very quickly. The sharks tend to bite their prey in half (to prevent the prey from swimming away), and death occurs by loss of blood within a couple of minutes. The killer whales generally do the same (e.g. sea lions, NS:RAL:73ff]).

c. The context of these types/duration of death is instructive:
  1. Relative to disease: Animal diseases are likely the closest we get to real "suffering" of a significant type. Deaths by predators are dominantly swift, and often almost instantaneous, but diseases can create prolonged degradations of visceral health. Those sensory functions of the higher mammals which monitor 'homeostasis' would reflect this out of balance condition, surely. Of course, if the damage by the disease gets severe enough, the animal will be likely taken as prey. We know that large numbers of animals (especially birds and small mammals) die of 'natural causes', since we have whole areas of research directed at carrion decomposition processes (cf. X01:CDDAW). Disease itself would have time to produce 'discomfort' within a higher animal, although the subjective elements of this might entirely escape such an animal. What we can say, however, is that the quick-death scenario of some predation is much more 'humane' than long term disease scenarios (remember the goldfish euthanasia page mentioned above?).

One well-respected animal welfare expert makes this point [PH:ATMS:115]: "The death of diseased seals is something that counts against the welfare of the seals in a way that the death of ageing seals, or even healthy seals by normal hazards of the sea (the price they pay for freedom) is not"

2. Relative to life spans: For prey animals in our possible "consciousness" range, life spans are measured in years and even decades, in the case of the very large animals. Most lives are spent in simple "good" lives of daily activities, reproduction, rearing of young, building of habitat. Apart from disease and accidents, animals do not live with "pain" for very long, for chronic or severe pain would quickly render them a target for a quick kill by a predator. What this means is that the suffering of the end-of-life event is either (1) minute compared to a relatively 'full' life for an animal; or (2) a merciful ending to some long-term suffering (cf. The description by the ecologist Colinvaux of this as "euthanasia" above).

5. "But this still seems like a dominantly antagonistic system--struggle, competition, death"

I think this may be a "marketing" issue...

If we zoom out and ask what are the possible types of interactions between organisms, the 'textbook' list is:

a. Predation -- one benefits, one is damaged

b. Commensalism -- one benefits, one not affected

"a relation between individuals of two species in which one species obtains food or other benefits from the other without either harming or benefiting the latter. The commensal (the species that benefits from the association) may obtain nutrients, shelter, support, or locomotion from the host species, which is substantially unaffected. The commensal relation is often between a larger host and a smaller commensal; the host organism is unmodified, whereas the commensal species may show great structural adaptation consonant with its habits, as in the remoras that ride attached to sharks and other fishes. Both remoras and pilot fishes feed on the leftovers of their hosts' meals. A commensal relation based on shelter is seen in clown fishes (Amphiprion percula), which live unharmed among the stinging tentacles of sea anemones, where they are protected from predators. Numerous birds feed on the insects turned up by grazing mammals, while other birds obtain soil organisms stirred up by the plow. Various biting lice, fleas, and louse flies are commensals in that they feed harmlessly on the feathers of birds and on sloughed-off flakes of skin from mammals. " [EBE:s.v. "commensalism"]
c. Mutualism -- both species benefits
  "association between organisms of two different species in which each is benefited. Mutualistic arrangements are most likely to develop between organisms with widely differing living requirements. The partnership between nitrogen-fixing bacteria and leguminous plants is an example, as is the association between cows and rumen bacteria (the bacteria live in the digestive tract and help digest the plants eaten by the cow). The associations between tree roots and certain fungi are often mutualistic (see mycorrhiza.) (see also Index: cattle) Intestinal flagellated protozoans and termites exhibit obligative mutualism, a strict interdependency, in which the protozoans digest the wood ingested by the termites; neither partner can survive under natural conditions without the other. Acacia ants (Pseudomyrmex ferruginea) inhabit the bull-horn acacia (Acacia cornigera), upon which they obtain food and shelter; the acacia depends on the ants for protection from browsing animals, which the ants drive away. Neither member can survive successfully without the other, also exemplifying obligative mutualism. The yucca moth is dependent on the yucca plant and vice versa: the moth acts as pollinator at the same time that she lays her eggs in the seed pods of the yucca; the larvae hatch and feed on some but not all the seeds. Both organisms benefit: the plant is pollinated, and the moth has a source of food for its larvae. [EBE:s.v. "mutualism"]
Which of these are the most 'spectacular'? Predation, of course--just watch wildlife documentaries!

Which of these are the most pervasive? Mutualism! (but it is poorly

"In attempting to unravel Darwin's entangled bank and understand how these interactions form the basic structure of communities, many popular accounts of community ecology focus on extravagant antagonistic displays between species. Although aggressive behaviours are important interspecific interactions, the amount of attention that is focused on them may create the incorrect impression that they are more important than other types of interaction. Mutualistic interactions between species are just as integral to the organization of biological communities as antagonistic relationships, with some mutualistic interactions forming the most basic elements of many communities...Some mutualistic relationships are so pervasive that they affect almost all life-forms. The root systems of most terrestrial plant species form complex associations with the soil microorganisms. These mycorrhizal associations aid the plant in taking up nutrients. In some environments, many plants cannot become established without the aid of associated mycorrhizae. In another relationship, legumes rely on nodule-forming associations between their roots and microorganisms to fix nitrogen, and these nitrogen-fixing plants are in turn crucial to the process of succession in biological communities. Mutualistic associations between animals and microorganisms are equally important to the structure of communities. Most animals rely on the microorganisms in their gut to properly digest and metabolize food. Termites require cellulose-digesting microorganisms in their gut to obtain all possible nourishment that their diet of wood can provide...In many terrestrial environments, mutualisms between animals and plants are central to the organization of biological communities. In some tropical communities, animals pollinate the flowers and disperse the seeds of almost every woody plant. In turn, a large proportion of animals rely on flowers or fruits for at least part of their diet. [EBE: s.v. "mutualism"]

"Ecology textbooks have generally underemphasized or even ignored symbionts and mutualists, yet they compose most of the world's biomass. Almost all the plants that dominates the world's grasslands, heaths and forests have roots intimately associated with fungi. The polyps of most corals contain unicellular algae, many flowering plants depend on insect pollinators and a very great number of animals carry communities of microorganisms within their digestive systems...Mutualism are represented in a much more varied range of species interactions than competition, predation and parasitism..." [NS:Ecol:482]

The world of nature is characterized by "more good than bad" and vastly so...And the vast majority of species interact with "peaceful cooperation" by definition of ecological niche (Colinvaux, above).

6. "But why do they have to be killed anyway? Why not let them die naturally? In fact, why do they have to die at all?!"

Let's start with the last question first--why do they have to die at all?

And the basic answer is two-fold: because (1) the individual needs to return the nutrients they 'borrowed' from the ecosystem, after using them for years and/or (2) the group needs to not 'hog' all the nutrients through unlimited growth/reproduction.

The first "fold" of this principle is relatively simple: after an animal or plant has lived a life, using food resources, minerals, and territory, it must return these to the "pool of resources" somehow, for other generations of life to use for growth and diversity.

Let's look at a couple of statements and illustrations of this first:

"Of course, if plants continually 'mined' soil and water for nutrients, these substances would soon be virtually exhausted...and life would nearly ground to a halt. Fortunately, a mechanism for restoring nutrients to soil and water exists. It consists of a little recognized but essential group of organisms known as decomposers. These are mostly obscure creature such as bacteria, fungi, soil insects, and worms. Decomposers make their living by digesting the wastes and dead bodies of other organisms. They break down laboriously created organic molecules into their simple chemical constituents and return them to soil (or water) from which plants can reacquire them." [X01:MON:36f]

"Unlike the energy of solar radiation, nutrients are not in unalterable supply, and the process of locking some into living biomass reduces the supply remaining to the rest of the community. If plants, and their consumers, were not eventually decomposed (tn: requiring death of some type!), the supply of nutrients would become exhausted and life on earth would cease. The activity of heterotrophic (tn: "eats others") organisms is crucial in bringing about nutrient cycling and maintaining productivity." {NS:Ecol:745]

"For photosynthesizers the supply of solar energy can be considered essentially unlimited, but not the supply of inorganic matter. As an example, suppose that we isolated a species of green plant in an otherwise sterile field and allowed its population to grow. If this plant species were a very tall tree, it might consume the entire supply of essential nutrients that its roots could reach in the soil. All chemical elements in the soil that are used by plants would then be incorporated into the tissues of the trees. (This example is not so farfetched as it might seem. In tropical rain forests, the soil often has few useful mineral nutrients, because rain washes very small molecules away. If the trees are removed, one or two seasons of crops will exhaust the few remaining nutrients.)

"At this point growth would stop for lack of materials. When some of the leaves or other tissues died and were broken up into molecules small enough for the roots to absorb, further growth would be possible.

"This would be a very slow process in our sterile field; still undecomposed plant remains have been found in peat and coal deposits of great age, despite evidence of microbial action. In our example, there were no organisms such as boring insects, bacteria, or fungi which normally break up dead plants. Only weathering and physical breakdown of the large molecules would occur. Under these unusual conditions, it is difficult to predict what might happen, but the trees would almost certainly die and fall to the ground because of inevitable accidents, storms, etc. Since decomposition in the sterile field would be relatively much slower than it is in the real world, the field would eventually become a jumble of dead trees, with a few living spindly individuals growing at a rate determined by the rate of supply of inorganic matter released by the physical decomposition of the dead trees.[X01:BP:164-165]

"The rapid decomposition of plant and animal products: leaf litter, animal carrion and dung, ensures the rapid return of resources bound up within them to the ecological system. The efficient release and recycling of this material is clearly a matter of considerable importance." [X01:CDDAW:1]

The second "fold" of this principle has to do with "balance" in nature: all species need to "stay in their niche" and biological constraints on growth (including death) are important to keep the ecosystem healthy.

Let's try to draw out the logic of these (using our existing world). A quite simplified version might look like this (the example is a terrestrial system of woodlands):

We start with an ecosystem that has (1) a continual supply of energy pouring into it (sunlight) and (2) a fixed amount of inorganic nutrients in the soil/sea.

Plants draw upon these two resources: sunlight (of which they only use around 1% of the available energy) and inorganic nutrients (which they get from the soil or the top layer of water in aquatic settings). The plants convert this (inorganic) energy into (organic) plant tissue (biomass). If plants did not die, they would soon use up all the inorganic nutrients in the soil. The results would be stunted plants, and no new plants. (See the description of this immediately above).

But most plants lose their leaves each year, and herbivores only eat about 10% of plant tissue (terrestrial systems only). So, the forest floor is brown each year. But the dead leaves are no good to the plants--the plants did a great job of locking the nutrients up into organic compounds, with tough cellulose walls.

So, in order to recycle the nutrients, we need to have at least two things: something to chew the plant matter (in order to break through the strong cell walls) and something to then convert the cell contents back into inorganic nutrients. This first need (breaking up the cell walls) is dependent on physical factors (e.g., trampling by animals) and chewing action by detritivores (e.g., snails, insects). The second need (the conversion) is accomplished by bacteria and fungi.

And immediately, therefore, we need some animals with motion (to move to the site), some animals with chewing and eating parts. And thus we have bacteria, fungi, insects and other small invertebrates. [We also are going to need tons of flying insects to do the pollinating of the plants.]

And we already need a system of predation...rates of reproduction of the bacteria alone are a problem:

"If bacteria reproduce every 20 minutes, exponential growth for 36 hours would produce a layer of bacteria a foot deep over the earth, which in the next hour would be over our heads."[X01:BP:121]
Plants won't get any sunlight, if it is blocked by a column of bacteria 6 feet tall, so we need some 'regulating system' to keep the bacteria "in check" as they are enjoying their meals.

And the system cannot be one-for-one: I cannot have a bacteria predator that is big enough to 'swallow' a bacteria, that only eats ONE bacteria (a one-for-one replacement) or the problem only gets worse! I have to have a predator who eats multiple bacteria, which indicates a need for mobility--to be able to move around to the various bacteria. And the energy costs of motion are quite high--our little predator has to eat a few MORE bacteria to accomplish this task. And we already have a food pyramid--just to keep the plants alive.

But our little bacteria predator will not be able to move around as quickly as the bacteria reproduce (their fast reproduction was part of the problem to begin with), so we will always have enough bacteria to decompose the dead plant tissue, and most bacteria will have 'long, full lives' for a bacterium.

As you can imagine, we will likely have to have a control predator on this first predator, with the same dynamics, and will increased motion ranges. As the pyramid gets taller, the prey gets physically further apart, and the number of 'eatings' diminish quite rapidly. [They also decrease proportionately, since metabolic rate (i.e., the need to eat!) decreases rapidly with body size.]

But why do they have to be killed? Why couldn't we just let them die? The answer, at the very bottom of the pyramid, is simple: they wouldn't die at all!

"In some organisms, however, extensive and apparently indefinite growth takes place and reproduction may occur by division of a single parent organism, as in many protists, including bacteria, algae, and protozoans." [EBE: s.v. "Biological Growth and Development: MEASUREMENT OF LIFE-SPAN"]
And this extends further than one might suppose:
  "Some organisms seem to be potentially immortal. Unless an accident puts an end to life, they appear to be fully capable of surviving indefinitely. This faculty has been attributed to certain fishes and reptiles, which appear to be capable of unlimited growth." [EBE: s.v. "Biological Growth and Development: MEASUREMENT OF LIFE-SPAN"]
And, as we go up the pyramid--especially with the insects--they will reproduce much, much faster than they die (the North American cockroach, for example, lives 6-7 years and lays well over 800 eggs). Because they are so subject to environmental threats (esp. weather and habitat destruction), they lay massive amounts of eggs to ensure they continue. And, this means their litter-sizes can vary from "none" to "massively too many"!

This will necessitate a higher ratio of predator to prey than perhaps we see higher up in the pyramid. [Remember, we also needed insects for pollination--and we need a way to feed these insects, which is largely through plants as food, which will require more plant growth, requiring more nutrients.]. And, because insects are known for "population outbursts" that vary geographically, we are going to need a highly mobile (and flexible) predator force to help these outbursts not eat all of their resources (and reduce their subsequent survival as a population). And so we get birds...

We could (and do) have 'same type' predators, in which some insects eat/destroy other insects, and this might keep the pyramid shorter. And this basically works...the insectivorous insects and parasitoids are of critical importance in helping insect orders "contain themselves", in the midst of their thriving!

But we know from population studies that the next higher levels of predators (e.g. vertebrates) do NOT make a meaningful difference in controlling the population immediately below them--so why do we need these 'fearsome creatures' with their killing methods (even if the highest levels, mammals preying upon mammals, are statistically insignificant and generally quite 'humane')? What good do they do?

Well, there are a couple of major values that they add:

a. they weed out the sick and old from the animal populations, allowing robustness in group populations (remember the zoologist's description of a farmer's selective breeding program above)

b. they weed out the sick and old from the animal populations, allowing nutrient reuse/recycling to get started

c. they reduce the excess of prey populations, reducing the intraspecific competition and conflict for resources (both within the group and between groups)

d. they increase community biodiversity(!)--consistently, in robust communities with high interspecies competition, they are the catalysts for keeping specie diversity high (or growing), which, by the way, is the major determinant to community stability [X01:BP:158] .

e. they participate with mammalian herbivores in large-distance nutrient transport ("Mammalian herbivores may also expedite the flow of nutrients between habitats. Large mammals in the Serengeti transfer great quantities of nutrients from the understories of tall grass savanna to adjacent open grasslands." [X01:PAI:169]) and their carcasses also move nutrients around.

f. as generalist feeders (in most cases), they exert a 'pruning' influence on local communities. When one food source is more available, they eat that. When a different one becomes more plentiful or more easily caught, they eat that. Carnivores have long been known to "eat what they can get". This is not enough to 'control populations' but it does 'trim and shape the hedges' a little.

g. they also recycle the bound-up nutrients before a dead mammalian carcass can do damage to the plant ecosystem. In other words, they eat the meat 'earlier than' the beginning of the decay process (death), minimizing the effects of carrion 'poisoning'. This has the effect of diverting nutrients from the decomposer cycle (temporarily, of course) to a living being, and to reproductive growth. It essentially keeps the caloric ball 'up in the air' longer, before it has to start the cycle all over again.

(Note: "During its decay, the processes going on inside a carcase have a marked effect on the soil and vegetation beneath and immediately surrounding the carrion. Leached materials soak into the soil beneath the corpse and the normal fauna of the soil is replaced by a carrion characteristic community. The effect--which may persist for many months--can be detected to a considerable depth below the carcase and at quite some distance from it. Vegetation is often killed and the area may take over a year to recolonize. While these effects have been most studied in temperate areas, a similar situation has been reported from East Africa: materials soaking from elephant carcases during decay formed a pool around the carcases and killed all vegetation beneath them." [X01:CDDAW:20])

Because of their minutely small numbers, they are not very 'expensive' to the ecosystem (recall the calculations for the 3 fox-units above), relative to their contributions above.

But why couldn't these big animals (or all animals, for that matter) be photosynthetic? All of us green-skinned and never having to eat anything?

The answer to that is rather simple:

  1. We couldn't move--there isn't enough energy made by photosynthesis to support an active/mobile organism of our/their size and activity level;

  2. We would either need roots, to get the soil nutrients, or mobility to go dig them up and eat them--requiring more energy; and

  3. We would still have the decomposition problem that started this discussion...

But why couldn't they be herbivores or insectivores instead of carnivores? They sorta are a little (as we documented above) but we really need them to be carnivores (or at least we need them to be 'selective killers')--if you look at the value list above.

And when they die and become carcasses, they get recycled by a scavenger, and/or get decomposed by the bacteria and fungi (above) into inorganic nutrients for some other organism to 'borrow' for its lifetime.

The above sketch is very, very simplified, but at least demonstrates some of the factors that must be present for life to exist at all, and to exist in some robustness.

Which brings us to the next question in the question: but why can't prey just die naturally, of old age? Why do they have to be actively killed by a predator?

Strangely enough, this quick death will actually be the most 'humane'.

A couple of observations will bear this out:

1. We have already pointed out that death by slow disease is the least preferable way of death. Not only is this likely the closest thing we have to our "long-term suffering", but disease can also affect the healthy group by (1) contagion and (2) diversion of (scarce) resources to the dying individual. Although the higher mammals are known to care for the sick sometimes, they are notoriously inconsistent in this, sometimes attacking and killing the victim themselves [PH:GN:83-85].

2. "Dying naturally" or "of old age" is essentially some type of organ (e.g., heart, lung, liver) or system (e.g., nervous, digestive, vascular) failure. These types of death DO occur (at least they do in captivity), but they are almost always long processes (like disease) as well. Generally it is disease that leads to organ failure anyway, so these two are closely related. The story de Waal gives about the death of the simian who died of heart failure, due to massive internal infections that had gone on for at least three months, with declining affect and vitality, illustrate the point [PH:GN:55f].

["Old age" (senescence) in mammals is accompanied by definite metabolic and vitality reductions, which generally is accompanied by disease.]

The timing of this is interesting. The "active community life" of a large animal would generally be considered the span of time in which they could contribute to that community, often simply the reproductive period. Most of the larger animals that are candidates for "agony" live deep into their contributory years:

"Whales, elephants, apes, and other large mammals in the wild... live through 50 percent or more of their reproductive spans, and a few survive beyond reproductive age" [EBE: s.v. "Biological Growth and Development: NATURAL HISTORY OF AGING: Reproduction and aging"]
But with old age comes loss of territory ("Most often the young animal has a small territory but defends a larger one as he gains experience, then gradually loses it as he reaches old age" [EBE: s.v. "Animal Behaviour: Dynamics of social behaviour: COSTS AND GAINS"]), which means loss of access to choice food supply (in some cases) and loss of status ("An individual weakened by injury, disease, or senility usually moves downward in rank" [EBE: s.v. "dominance hierarchy"]), which means less food allocation in shared food supplies. But in all cases of post-reproductive periods ("old age"), the individual is no longer contributing significantly to the growth of the group, yet still consuming scarce resources. Since death by disease (the normal cause of death by "old age") is more painful and less likely to be correlated chronologically with loss of "contribution", the fact that such animals are taken swiftly around this time may again be the most humane system.

[Also, in the smaller mammals and birds, 'non-predator' deaths apparently are more common, for the carcasses of these are the object of considerable field research for those studying the decomposer cycle (e.g. X01:CDDAW)]

Additionally, if everything died a natural death, we would have a major practical problem--how to stop the carrion decay process from killing all the plants! We noted above the problem carrion communities create:

"During its decay, the processes going on inside a carcase have a marked effect on the soil and vegetation beneath and immediately surrounding the carrion. Leached materials soak into the soil beneath the corpse and the normal fauna of the soil is replaced by a carrion characteristic community. The effect--which may persist for many months--can be detected to a considerable depth below the carcase and at quite some distance from it. Vegetation is often killed and the area may take over a year to recolonize. While these effects have been most studied in temperate areas, a similar situation has been reported from East Africa: materials soaking from elephant carcases during decay formed a pool around the carcases and killed all vegetation beneath them." [X01:CDDAW:20]

In other words, if every animal turned into a carcass (which feeds bacteria and then plants) instead of a meal (which turns into new animal pups, individual growth, and animal community development), we would have the immense logistics problem of how to make sure there was always a carnivore close by when an animal died--so they would eat the carrion before it began the decay process.

You can probably appreciate the sheer logistical problem this would entail (image the linear programming challenge!), and perhaps even visualize the image of a group of predators-turned-scavengers, just hanging around (like vultures in the cartoons) waiting for the old zebra to die...And, since death is not very predictable, unless you precipitate it by predation, our predators-turned-scavengers (and their families) would go hungry more often than not--not a very workable scenario, to say the least.

But there is another aspect of "natural death" that we need to consider before we 'romanticize' it: the length and suffering entailed in most organ failures. Failure of organ systems, such as kidney, liver, heart, lungs is generally a long-term affair, involving considerable personal suffering (and debilitation). A simple glance at any medical resource, describing the symptoms and duration of these conditions, would quickly convince one that it is not necessarily less painful than breaking one's spinal cord! When the ecologist used the word 'euthanasia' (NS:WBFCAR) in describing the actions of large predators, there is a powerful truth hiding in there, I suspect...


Well, we are the end of the biological detail section. Let me try to summarize and make a few observations in the process:

1. The vast, vast majority of living creatures could not/do not experience agony or suffering. We came up with only 14.6k species (out of 1.55M) that could experience 'agony' at all...a whopping 0.94%...[If we counted the number of individuals, as opposed to species, the number would be infinitesimally small.]

2. If these agony-possible creatures could experience suffering (through the presence of consciousness), this consciousness would likely be on a spectrum, with primates being 'high' and birds being 'low'. This would mean that the suffering of a bird or rat would be much lower than that of a chimp. And this would mean that the higher the rate of predation (more smaller victims than large), the less the capacity for suffering to begin with.

3. We found that only 20% of the predatory species actually kill their prey--mostly the prey survives. This means that "preying to the death" is a small fraction of the species considered "predatory" (including herbivores).

4. There are more life-forms that eat food killed by others, than life-forms that kill what they eat.

5. Parasitism, in which the prey does not die, and of which often the host is unaware (of the presence of the parasites) is much more common than "killing predation" (with parasites being as many as half of all living species).

6. The combination of the scavengers and the parasites--neither of which kill their food--accounts for well over 2/3 of all species.

7. Even the truly awesome, large predators often eat what they did NOT kill (i.e., they scavenge), and most tend to omnivory. [Every calorie of plant tissue "substitutes for" a calorie from meat, reducing the amount of predation necessary...]

8. There are many more species (by a factor of 10) that derive life from a host without killing it; than there are predators who kill.

9. Any possible conscious suffering is more likely to occur higher up on the food pyramid, where the numbers of actual individuals being killed will be minute to that below it...In other words, the more numerous and frequent are the deaths that occur per unit time, the less likely there is ANY 'suffering' at all. [For example, the largest number of 'deaths' might be tiny zooplankton eating tiny phytoplankton, but there is no feeling or agony there in the least...The more death there is at a trophic level, the more likely it is completely "painless".]

10. Most healthy individuals in a species are NOT the targets of predators, contrary to popular opinion.

11. Most predators are unsuccessful, the majority of the time (the prey escapes).

12. Most large prey animals live full lives anyway: "Whales, elephants, apes, and other large mammals in the wild... live through 50 percent or more of their reproductive spans, and a few survive beyond reproductive age" [EBE: s.v. "Biological Growth and Development: NATURAL HISTORY OF AGING: Reproduction and aging"]

13. The observational data demonstrates that, for the vast majority of a prey animal's lifetime, the predator/prey interactions are not "anxiety producing" at all.

14. Our current understanding of ecological "niches" leads us to the conclusion that the vast majority of interspecies relationships are "peaceful coexistence" (as opposed to constant 'gladiatorial' competition).

15. "the lives of big game animals are lived in a large measure of freedom from the awful world of tooth and claw that we can conjure up by a careless reading of Darwin. " [X01:WBFAR:156] It would seem that this 'struggle' to survive is perhaps less of a struggle and more of an occasional nuisance or periodic hassle...

16. There are a couple of powerful factors built into the system that 'encourage' predators to kill their prey as quickly as possible (i.e., with as short a period of pain, and as low an intensity of pain, as possible). These forces are constantly at work, minimizing suffering in every act of predation.

17. The facts of how death occurs for much/most prey is consistent with these factors, and in the vast majority of the cases (smaller mammals and birds) death is instantaneous, and in the higher mammals most deaths are either instantaneous (spinal) or swift (asphyxiation). [The exceptions are when animals attack prey larger than themselves in groups, but the trade-off is more suffering from one prey (yet still measured in the 5-10 minute range) versus less actual individuals killed.]

18. The quick-death scenario of most predation is much more 'humane' than long term disease scenarios, and the very similar 'natural death' process.

19. All of the obvious hypothetical scenarios (e.g., all animals photosynthetic, all animals herbivores, all predators wait until the prey dies 'naturally') run into major logistical challenges, energetic system problems, or don't solve the basic problems anyway.

20. Predation, of the kind actually practiced in nature (i.e., mostly old/sick victims, merciful killing methods, non-terrorizing effects on prey life-styles, minimal impact on population size, positive impact on community life, agony limited to vast minority of prey species, long prey life spans), is by far and away the most humane way for the prey individual, and the most practical way to ensure that life continues, grows, diversifies, and shares the nutrients with each succeeding generation.


It is mind-boggling to see how clever and how 'merciful' this macro-system actually is: by "restricting" agony-possible species to very high up on the food pyramid, where the number of deaths are relatively minute and the manner of death relatively painless, the overall suffering in the system has been minimized to the extreme--without compromising the beauty, stability, and awesomeness of biodiversity...even in a fallen world, which still joyously anticipates an even better one...

So, the original statement of "ALL", "DEATH", and "AGONIZING" is happily mistaken, and the statement by J.S. Mill seems almost comical at this point (but I suppose even comedy has some It would thus seem that the practice of painful predation is not so ubiquitous after all, and actually constitutes a very minute fraction of the experience of life on earth. One can give examples of horrible death-events observed in the wild, and advance anecdotes of animal cruelty, of course, but the overall pattern is quite, quite clear: painful predation is statistically minute in the overall scheme of life.

The world of nature seems (from our analysis above) to be wonderfully characterized by "more good than bad" and vastly so (in keeping with the general sketch we made of the biblical data)...all creatures have their roles to play, their start/stop times, their habitats to build/manage, their ecological community contribution to make, their food to catch, their relationships to experience, their kids to raise, and then to yield their resources to the next generation...including me..."There is an appointed time for everything. And there is a time for every event under heaven—A time to give birth, and a time to die" (Ecc 3)

"His eye is on the sparrow, and I know He watches me..."

[Back to the Table of Contents for Predation]
[ pred2.html  ]

From: The Christian ThinkTank...[] (Reference Abbreviations)