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From:
Peter Brandt <[log in to unmask]>
Date:
Fri, 24 Apr 1998 23:11:06 -0500
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A friend pointed me to an interesting article by the Vegetarian Resource
Group called "Humans are Omnivores".  I believe most of the content of the
article also appeared in "The Vegan Handbook" that has been quoted in both
Tom Billings' & Ward Nicholson's writings.  The article can be found at:=20

http://envirolink.org/arrs/VRG/omni.html

Best, Peter
[log in to unmask]

****************************************************************************

                             Humans are Omnivores

                     Adapted from a talk by John McArdle, Ph.D.

     Document Sections:=20

     Introduction=20
     Confusion between Taxonomy and Diet=20
     Omnivorism=20
     The Great Apes=20
     Evidence of Humans as Omnivores=20
          Archeological Record=20
          Cell Types=20
          Fermenting Vats=20
          Jaws=20
          Salivary Glands=20
          Intestines=20
     Conclusion=20
     APPENDIX: Further Evidence=20
     For Questions or Comments=20


Introduction

There are a number of popular myths about vegetarianism that have no
scientific basis in fact. 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.=
=20

Confusion between Taxonomy and Diet

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.=20

Members of the mammalian Order Carnivora may or may not be exclusive meat
eaters. Those which eat only meat are carnivores. 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.=20

Omnivorism

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). 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.=20

The Great Apes

There are very few frugivores amongst the mammals in general, and primates
in particular. 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. Orangutans are similar,
with no observations in the wild of eating meat.=20

Gorillas are more typically vegetarian, with less emphasis on fruit.
Several years ago a very elegant study was done on the relationship between
body size and diet in primates (and some other mammal groups). The only
primates on the list with pure diets were the very small species (which are
entirely insectivorous) and the largest (which specialize in vegetarian
diet). However, the spectrum of dietary preferences reflect the daily food
intake needs of each body size and the relative availability of food
resources in a tropical forest. 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).=20

Evidence of Humans as Omnivores

Archeological Record

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. Once domestication of food sources
began, it included both animals and plants.=20

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.=20

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.=20

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.=20

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. 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.=20

Salivary Glands

These indicate we could be omnivores. Saliva and urine data vary, depending
on diet, not taxonomic group.=20

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.=20

Conclusion

Humans are classic examples of omnivores in all relevant anatomical traits.
There is no basis in anatomy or physiology for the assumption that humans
are pre-adapted to the vegetarian diet. For that reason, the best arguments
in support of a meat-free diet remain ecological, ethical, and health
concerns.=20

[Dr. McArdle is a vegetarian and currently Scientific Advisor to The
American Anti-Vivisection Society. He is an anatomist and a primatologist.]=
=20

APPENDIX: Further Evidence

The following information is taken from The New York Times, May 15, 1979.
According to Dr. Alan Walker, a Johns Hopkins University anthropologist,
Homo Erectus, the species immediately ancestorial to our own Homo Sapiens,
had evidence of an omnivorous diet. Every Homo-Erectus tooth found was that
of an omnivore. However, a small  sample of teeth from the human-like
species during a 12 million year period leading up to the Homo-Erectus
period, indicates the earlier species may have been a fruit eater. Even if
this species, way before our own, lived on a fruit diet, they probably
would not have consumed what we consider typical fruits. Hundreds of plants
produce fruits that are tougher, more substantial foods than what we eat
today.=20

Quoted from an editorial by William Clifford Roberts, M.d., Editor-in-Chief
of the American Journal of Cardiology:=20

     "When we kill animals to eat them, they end up killing us because
their flesh, which contains cholesterol and saturated fat, was never
intended for human beings, who are natural herbivores."=20

Quoted from "WHAT DID OUR ANCESTORS EAT?" in Nutrition Reviews, by Stanley
Garn,
Professor of Nutrition and Anthropology, and William Leonard, Assistant
Professor of Human Biology:=20

     "These people of Upper Pleistocene, and later those of the mesolithic,
were our
     immediate ancestors, no longer hunters exclusively and with
whole-grain products        and a variable amount of roots, fruits, leafy
vegetables and nuts in their diet. We      must grant them a mixed diet,
with animal fat providing a smaller proportion of         their food energy
than was probably true for the Neanderthals."=20

For Questions or Comments

For questions or comments on this article, please contact Brad Scott at
[log in to unmask] This article may be reproduced for
non-commercial use intact or with credit given to The Vegetarian Resource
Group.=20

This article was originally published in the May/June 1991 edition of the
Vegetarian Journal, published by:=20

      The Vegetarian Resource Group
      P.O. Box 1463, Dept. IN
      Baltimore, MD  21203
      (410) 366-VEGE

The Vegetarian Resource Group (VRG) is a non-profit organization dedicated
to educating the public on vegetarianism and the interrelated issues of
health, nutrition, ecology, ethics, and world hunger. In addition to
publishing the Vegetarian Journal, VRG produces and sells cookbooks, other
books, pamphlets, and article reprints.=20

For more information, send a stamped self-addressed envelope to the above
address. Subscriptions to the Vegetarian Journal are $20 per year (6
bi-monthly issues). All contributions above the $20 subscription are
tax-deductible to the full extent allowed by law. Contributions help VRG
promote vegetarianism.=20

             =A9 1997 The Vegetarian Resource Group=20
             PO Box 1463, Baltimore, MD 21203
             (410) 366-8343 Email: [log in to unmask]

    Last Updated
   March 29, 1997
    [log in to unmask]
                     Graphic design
                            by=20
                                             =20
 Please visit our new site at www.vrg.org

 The contents of this web site, as with all The Vegetarian Resource Group
 publications, is not intended to provide personal medical advice. Medical
 advice should be obtained from a qualified health professional.=20

 Any pages on this site may be reproduced for non-commercial use if left
 intact and with credit given to The Vegetarian Resource Group.=20


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