A rational critique of:

Humans are Omnivores
Adapted from a talk by vivisectionist John McArdle, Ph.D.

This article was shamelessly published in the May/June 1991 edition of the Vegetarian Journal


JM>  There are a number of popular myths about vegetarianism that have no scientific basis in fact.
    And, unfortunately, there are many more annoyingly-popular pseudo-scientific myths, masquerading as science, that humans are "omnivores"; those in this article will be refuted.

JM>  One of these myths is that man is naturally a vegetarian because our bodies resemble plant eaters, not carnivores. In fact we are omnivores, capable of either eating meat or plant foods. The following addresses the unscientific theory of man being only a plant eater.
    We will find that JM consistently fails to support his thesis with real science by erroneously substituting cultural practices for scientific facts and conclusions, the most common and fatal error of those falsely claiming than humans are "omnivores".

Confusion between Taxonomy and Diet

JM>  Much of the misinformation on the issue of man's being a natural vegetarian arises from confusion between taxonomic (in biology, the procedure of classifying organisms in established categories) and dietary characteristics.
     Right, these 'classifications' are Linnaean nomenclature which is archaic, out-of-date, and based on insignificant, fragmentary fossilized data alleging to track the human lineage, which should be completely overhauled in light of modern genetic research.  JM, a claimed "anatomist and primatologist" at the PhD level, should be aware of this critical fact, and the profound differences between Nature and culture, but we will see that he is not, much to his own embarrassment.

JM>  Members of the mammalian Order Carnivora may or may not be exclusive meat eaters. Those which eat only meat are carnivores.
     This is the crux of the matter: "you will see that taxonomy is more of an art than a science", "that there isn't even solid agreement on which species belong in which orders", "A little confusion is probably a good thing to learn to accept when it comes to classifying animals."
    So, we see that this non-science and confusion dominate JM's faulty presentation, and it is a primary cause for his false conclusion that "Humans are Omnivores".  In fact, search as you will, there is no taxonomical classification as "omnivore".

JM>  Dietary adaptations are not limited by a simple dichotomy between herbivores (strict vegetarians) and carnivores (strict meat-eaters), but include frugivores (predominantly fruit), gramnivores (nuts, seeds, etc.), folivores (leaves), insectivores (carnivore-insects and small vertebrates), etc. Is is also important to remember that the relation between the form (anatomy/physiology) and function (behavior) is not always one to one. Individual anatomical structures can serve one or more functions and similar functions can be served by several forms.
    A little truth has leaked out.  These 'classifications' are mere conveniences, not strictly defined in a reasonable, rigorous, scientific manner.


JM>  The key category in the discussion of human diet is omnivores, which are defined as generalized feeders, with neither carnivore nor herbivore specializations for acquiring or processing food, and who are capable of consuming and do consume both animal protein and vegetation. They are basically *opportunistic* feeders (survive by eating what is available) with more generalized anatomical and physiological traits, especially the dentition (teeth).
    Notice, there is NO useful, meaningful, or even vaguely-scientific anatomical/physiological/biochemical definition of "omnivore", and JM foolishly ignores the inescapable fact that humans are totally incapable of killing, tearing asunder, and consuming raw their prey with their natural, biological equipment, as ALL natural omnivores do!  In fact, I have challenged people who adamantly claim that they are "omnivores" for over 35 years to prove they are natural "omnivores" by simply killing and eating raw a small animal with their natural equipment, and none has ever done so to actually test their irrational belief.  Not one!
   JM has made the all-to-common and fatal error in his totally unscientific and unsupportable claims by confusing Nature and culture; a grievous error which most grade school children would not make.  Humans are clearly not natural "omnivores".  Some are cultural "omnivores", and indeed must rely on cultural artifacts to raise, kill, butcher, cook, disguise with seasonings, cut up, and finally consume their animal prey.  Again, the false definition rests on the phrase "capable of consuming"; however, humans have no natural capability to do so.  If they did, they would.  Thus, relying on an absurd false definition, JM inevitably and inescapably comes to a false conclusion.
     Another insight into the falsity of this concept rests in the mistaken confusion, and proposed false-identity, of the verbs: to be, and to do.  Being refers to our genetic code and its consequences, while doing is totally unrelated and a consequence of cultural programming.
     Let's examine JM's muddled "thinking" a bit to see how completely absurd, and perhaps intentionally-misleading, the "capable" definition really is.
     Humans are "capable" of flying through the air; that makes us birds or flying insects, right?

     Humans are "capable" of traveling under water; that makes us fish or sea worms, right?
     Humans are "capable" of tunneling through the earth; that makes us earthworms or moles, right?

JM>  All the available evidence indicates that the natural human diet is omnivorous and would include meat. We are not, however, required to consume animal protein. We have a choice.
    Another unintentional admission that we are not natural omnivores; we have a choice; animals, however, do not have any choices, they rely on their genetically-programmed instincts to kill and eat animal prey.  Humans have no instincts to do so, in spite of the foolish claims of various Instincto cults.  Choices are cultural, not instinctual.  How can someone with even a trivial education not understand the profound difference between culture and Nature?

The Great Apes

JM>  There are very few frugivores amongst the mammals in general, and primates in particular.
    Totally irrelevant, we are apes, not "mammals in general" nor random primates.  Actually, we are Pongidae, only the horrendous human ego has chosen to elevate ourselves to another, exclusively ours, thus false classification.  With a genetic difference of a mere ~1.6% from the chimp, our closest genetic relative, it should be obvious that our diet should be essentially that of the chimp.  Clearly, the genetic distances from various, scientifically-indefinable natural "omnivores" would be much more, thus, again, refuting JM's unsupportable claim of "humans are omnivores".

JM>  The only apes that are predominantly fruit eaters (gibbons and siamangs) are atypical for apes in many behavioral and ecological respects and eat substantial amounts of vegetation.
    Whoops - chimps are frugivorous, eating mostly fruit when available, and falling back on leaves when sufficient fruit is not, and JM is claimed to be a primatologist.

JM> Our closest relatives among the apes are the chimpanzees (i.e., anatomically, behaviorally, genetically, and evolutionarily), who frequently kill and eat other mammals (including other primates).
    "Frequently" turns out to be a self-serving distortion, apparently for the sake of his pre-conceived and false conclusion, and for a "primatologist", it must be intentional.  Chimp hunting and flesh-eating is rare, ~1.4% of their diet, not practiced among all adults, as would be required by a true nutritional need, and is clearly cultural, since flesh is used to gain sexual favors --humorously-similar to human dating.

Evidence of Humans as Omnivores
Archeological Record

JM>  As far back as it can be traced, clearly the archeological record indicates an omnivorous diet for humans that included meat. Our ancestry is among the hunter/gatherers from the beginning.
    More muddled "thinking".  The "archeological record" so referenced is purely self-selecting, thus misleading, since that "evidence" is only produced by cultural processes, which include tool-marked bones and evidence of fire.  The true frugivorous, natural, non-tool-using, human would leave NO evidence at all, since all food wastes would be composted into oblivion.  Tools produce enduring evidence, raw-food eating humans do not; however, that certainly does not mean they did not exist. They exist today, and produce no long-term "archeological evidence" of their diet in the local ecosystems.

 JM>  Once domestication of food sources began, it included both animals and plants.
    Whoops -- once culture is in play, its effects can not be used to assess the natural human.  Anthro-apologists like to ignore this critical fact, thus reducing their verbal output to mere exercises in creative writing, certainly not real science.

JM> Cell Types
Relative number and distribution of cell types, as well as structural specializations, are more important than overall length of the intestine to determining a typical diet. Dogs are typical carnivores, but their intestinal characteristics have more in common with omnivores. Wolves eat quite a lot of plant material.
    Totally irrelevant to humans.  But, mindless insertion of irrelevancies that sound correct is a common ploy of anthro-apologists in order to created the illusion of scientific credibility.

JM>  Fermenting Vats
Nearly all plant eaters have fermenting vats (enlarged chambers where foods sits and microbes attack it). Ruminants like cattle and deer have forward sacs
derived from remodeled esophagus and stomach. Horses, rhinos, and colobine monkeys have posterior, hindgut sacs. Humans have no such specializations.
    Again, factual but totally irrelevant to humans, or the "omnivore" issue; this applies to herbivores, not frugivorous humans.

JM>  Jaws
Although evidence on the structure and function of human hands and jaws, behavior, and evolutionary history also either support an omnivorous diet or
fail to support strict vegetarianism, the best evidence comes from our teeth. The short canines in humans are a functional consequence of the enlarged cranium
and associated reduction of the size of the jaws. In primates, canines function as both defense weapons and visual threat devices. Interestingly, the primates
with the largest canines (gorillas and gelada baboons) both have basically vegetarian diets.
    Love that self-contradiction.

JM> In archeological sites, broken human molars are most often confused with broken premolars and molars of pigs, a classic omnivore. On the other hand, some herbivores have well-developed incisors that are often mistaken for those of human teeth when found in archeological excavations.
    Yes, archaeology is confused and mistaken.

JM> Salivary Glands
These indicate we could be omnivores. Saliva and urine data vary, depending on diet, not taxonomic group.
    "Could"?  Where is the evidence?  Without evidence, "could" and "could not" are identical.

JM>  Intestines
Intestinal absorption is a surface area, not linear problem. Dogs (which are carnivores) have intestinal specializations more characteristic of omnivores than carnivores such as cats. The relative number of crypts and cell types is a better indication of diet than simple length. We are intermediate between the two groups.
    More irrelevancies and errors to obfuscate the issue.  The surface area of a cylinder IS linearly proportional to the length.  We are "intermediate" between a carnivore and another carnivore, so what does that mean?

Conclusion (false)

JM>  Humans are classic examples of omnivores in all relevant anatomical traits.
    This is a blatant lie.  JM has presented no anatomical definition, or even an attempt to generate a rigorous, testable, anatomical definition of "omnivore"; this is not possible, since the anatomies of various natural omnivores is so diverse that no coherent patterns can be found.

JM>  There is no basis in anatomy or physiology for the assumption that humans are pre-adapted to the vegetarian diet.
   The "vegetarian diet" is generally cooked, is centered on grains and beans, and may include dairy and eggs; this was not a discussion of a "vegetarian diet".  Another irrelevant dodge and intentional obfuscation.

JM>  For that reason, the best arguments in support of a meat-free diet remain ecological, ethical, and health concerns.
    The "ethical" argument is totally bogus, since there is no objective set of ethics to which one can compare to determine what is more, or less, "ethical" than what.  That is, individuals just make up their own ethical standards to suit their purposes of the moment.  Hitler did what he did, based on his own personal set of ethics; so does JM.

[Dr. McArdle is a vegetarian and currently Scientific Advisor to The American Anti-Vivisection Society. He is an anatomist and a primatologist.]
    Clearly unqualified and hopelessly-confused on very fundamental facts and real science.  And he has a PhD; that's frightening.  Worse, look at some more of his hysterically-emotional nonsense.

This article was originally published in the May/June 1991 edition of the Vegetarian Journal, published by:
The Vegetarian Resource Group, P.O. Box 1463, Dept. IN Baltimore, MD 21203 (410) 366-VEGE
    Sad, really sad.  And these people are supposed to be "vegetarian" authorities?



Home page