Beyond Polemics

J S Coleman

Bionomic Nutrition Forum, 2001

"Interpretation of our past runs the constant risk of degenerating into mere 'paleopoetry' stories that we spin today, stimulated by a few bits of fossil bone, and expressing like Rohrschach tests our own personal prejudices, but devoid of any claim to validity about the past."
The Rise And Fall of The Third Chimpanzee, Jared Diamond, p.70, Vintage Science
"Criticism should not be querulous and wasting, all knife and rootpuller, but guiding, instructive, inspiring."
Ralph Waldo Emerson


The 'Beyond Veg' web site purports to be a thorough and scientific challenge to vegetarianism based on hard scientific facts and experiential evidence (anecdotes). It attempts to use paleontology, primatological evidence, evolutionary biology and comparative anatomy to rubbish the naturalistic vegetarian hypothesis. This article is intended not only to counter many of the claims of the authors of 'Beyond Veg', but also to reveal the authors terribly erroneous and unscholarly approach to science in pursuit of their dietary dogma.

Basic errors in logic and philosophy are dealt with in the first section and in the second section, an in-depth analysis of some of the more complex issues is presented.

Errors of logic

1) Argumentum ad Novitatem

- age of scientific information does not invalidate

The claim that the citation/evidence is "outdated" is not supported by any authoritative opinion. What van Lawick and Goodall observed was "omnivorous" behaviour, but even so, Stevens and Hume stated that the chimpanzee is generally a strict herbivore.

Scientific theory/evidence does not come with a sell by date, it has to be properly disproved or discredited. Stevens and Hume is a modern and authoritative text, and the authors have excellent credentials, unlike the authors of 'Beyond Veg'. As with chimpanzees, rabbits and many other animals classified as herbivores, they sometimes eat animal matter. This is sometimes called 'opportunistic feeding' when it is not very prolific, but even so, rabbits are classed as herbivores.

2) Argumentum ad hominem

- assaulting the person, and not the subject matter

But, how does one detect ones detractor's emotions via their written word? Of course, one does not; we infer other people's emotions, sometimes erroneously, ourselves. Anyway, are the detractors really so emotionally charged, and even so, this does not make their claims invalid, nor warrant assaulting them as part of supposedly scientific discourse.

3) Argumentum ad ignorantiam

- because we don't know about something, it does not exist

But maybe there was and we never knew about it! Absence of evidence is not evidence of absence.

4) Argumentum ad nauseam

- the size and amount of evidence presented does not reflect validity

Why isn't 'Beyond Veg' short and specific? If any authority working in the anthropological or biological fields has stated that humans are "omnivorous" that need to eat animal matter, why not just cite them, just show us the evidence and be done? Instead we see a long-winded and repetitive mess.

5) Audiatur et altera pars

- lack of supporting evidence

Countless of the claims of Beyond Veg are unsupported by scientific evidence, they are solely the often false and bizarre, beliefs of the authors.

The supporting evidence from millions of years of virtually unknown plant biology is?

Some plant foods, such as peanuts, are excellent sources of nearly all the essential minerals, and this includes iron and zinc. According to Leonard Mervyn (B.Sc., Ph.D., C.Chem, F.R.S.C) in 'Thorsons Complete Guide To Vitamins and Minerals', soft fruits "all supply good dietary intakes of potassium, calcium, phosphorus and iron."

The mineral content of plant foods depends mainly on soil content and condition. According to Dr. Duke's Phytochemical and Ethnobotanical Databases, Lettuce Leaf (Lactuca sativa L.) contains between 27 and 974 ppm (i.e. max. about 0.1 grams per 100 grams) of zinc. The RDI for zinc is 15 to 20 milligrams, thus 100 grams of best (zinc rich) lettuce provides nearly 5 times the RDI!

If modern plant foods can provide nutrition sufficiency, why not ancient ones?

6) Bifurcation

- presenting two options when more may be available

The meat eating frugivorous human does not have to live/die, they might just be slightly ill, and not to a sufficient level to significantly affect reproductive fitness! Of course, is it perfectly possible that meat eating/cooked food eating humans preferentially survived because they were better nourished in a harsh environment, but not necessarily because of any adaptation. Their survival habits would have been culturally transmitted, perhaps long beyond their initial advantage.

7) Non sequitur (with unstated inference)

- the conclusion does not follow from the observations

Is the intended inference that because anteaters like the aard-vark, echidna and pangolin eat an "extreme" (narrow/monophageous) diet, they are somehow incorrect? Do anteaters need to be more omnivorous and eat some plant matter, and are koala diets meat deficient? Variation is the normal in nature, and what is common or rare is irrelevant in establishing the correct diet of an individual species. Are we also to believe that because the chimps at Gombe eat insects, all chimps eat insects? Or, that because some gorillas eat insects and invertebrates, all gorillas do?

From this it is falsely claimed that ". . . Chivers prefers the term faunivore to indicate that humans are adapted to a diet that includes animal foods (fauna)." Chivers states that the gut dimensions of humans are by some abstract measure, similar to carnivores. Yet the stronger structural evidence, haustra, shows herbivorous adaptations. Chivers is only discussing gut morphology in isolation, and never "classes humans as faunivores". The observation does not disprove the hypothesis that humans are strict herbivore-frugivores. Carnivore dimensioned guts might also be a good thing to digest fruit.

These receptors might also serve well to soak up an animals own heme iron, leaking out as a result of intestinal injury, and thus prevent bacterial infection. The digestive system of a wild animal may need to take some abuse. The cell receptors of any animal cell, are quite likely to be able to take up similar chemicals found in other animal tissues - but this does not mean they are supposed to eat them.

How is that? First of all, plant foods are by no means devoid of vitamin B12. They usually contain pink pigmented facultative methylotrophs, bacteria that make vitamin B12, as well as being able to take it up from suitable soil. I had a box of Chilean raspberries, and the label claims that they provide 30% of the RDA of vitamin B12 per 100 grams. While there seems to be little evidence that modern humans can obtain their own supply via bacteria in the gut, this does not prove that our ancestors were similarly limited. Because B12 can be stored in the liver and last for 10 to 20 years, there is no need for a year-round supply. Indeed such an adaptation suggests an animal that can do without the vitamin for extended periods, much as the camel can store water in its blood, and so manage without it for a long time. A regular flesh eater would have no need of such adaptations.

But it does not follow from this that all animals are omnivorous. Monophages such as the anteaters and the koala do exist.

8) misplaced causation

e.g. Because (he alleges) most vegan raw diets fail, then the vegan raw diet causes malnutrition, but no attempt is made to examine socio-economic factors, the primary factor in nutritional status of human populations (how many raw food eaters are wealthy enough to eat well at all?)

9) omissions

As any PR hack knows, the best way of presenting your case in a positive light is to omit any contradicting facts. (see the second section for other major omissions)

Peanuts (and some other seeds/legumes/nuts) are 15% or more EFA, and we only require a few grams of EFA per day. Plant foods are the richest sources of EFAs, although they do not provide EPA and DHA. In the normal healthy cells of most populations, EPA and DHA can be manufactured from alpha-linolenic acid (LNA), which is found abundantly in plant seed oils. However some degenerative conditions may impair our ability to synthesize sufficient EPA and DHA from LNA. Certain populations and a few individuals are also affected by potentially deleterious mutations that impair the ability of their cells to synthesize EPA and DHA from LNA, but these tend to occur in traditional peoples who have depended on fish as a staple in their diets. According to Udo Erasmus, in his book 'Fats that Heal Fats that Kill', this affects between 2% and 10% of these populations involved. These people have to obtain preformed EPA and DHA in their diet. While fish manufacture EPA and DHA from LNA, they obtain most of it preformed from brown and red algae (Erasmus, op. cit., p.259).

10) contradictions

e.g. How can it be simultaneously claimed that "The morphology of the human gut does not correspond to that expected for a nearly 100%-fruit frugivore. . .", while at the same time maintaining that examples of animals eating such diets do not exist, and that all other apes eat leaves or animal products? Logically, if humans were uniquely adapted to a fruit only diet, then we would expect only them to have the unique anatomy for such a diet. And, the absence of any other examples would no more disprove the human-frugivore hypothesis, than singular case of the eucalyptus eating koala would be proven dietarily wrong, for its crime of being dietarily unique.

Errors in philosophy

1) confusing Lamarckism with Darwinism/does not understand evolution

This is actually a restatement of Lamarcks invalid second postulate about perceived needs, but unfortunately genes don't provide for any perceived needs. We know that about 99% of the species that ever lived are now extinct! Organisms don't just handily "adapt" to newer environments when they pop up - there is no reason to accept that because meat is eaten, favourable genes must exist to adapt. So, 'Beyond Veg' not only misunderstands a crucial aspect of evolution, it even puts invalid Lamarckism in its place!

This may be generally true, but it is not always the case. Sometimes a sudden environmental change can immediately remove genes from the pool.

2) Platonism

Platonism makes the error of suggesting that there are ideal forms ("essence") which are at the heart of complex systems. To suggest that because most apes eat some animal matter, and therefore apes are essentially "omnivorous", and then to take this abstract category and imply that humans should also be "omnivorous" to fit the normal, is an invalid platonic proposition. There is no average or ideal ape diet, other than in the ideas people have. This problem, which is often seen in biology, is explained in detail at the beginning of the next section. Examples are given below in the final sub-section The Paleopoetry Diet.

3) reification

Categories and averages are abstract concepts, they help us to think about things, but they do not describe any biological reality. When, for example, we create the abstract concept of intelligence to create a property reflecting certain kinds of intellectual performance, it does not follow that there is such a thing as intelligence. Instead many complex and dynamic processes influence the abstract property we are attempting to measure and call intelligence. Similarly a taxa organises organisms according to their perceived relatedness, not their real relatedness.

How scientific is comparative biology?

Before any meaningful debate can begin we need to understand the underlying philosophy of comparative anatomy. Is this paradigm scientifically acceptable? We note that the biological sciences are not exact empirical sciences -- they remain primarily descriptive, rather than experimental sciences. Classically, until the evolutionary theory and discovery of genes, fairly recently, the biological sciences have lacked an under-pinning theory (or "central dogma") and something to measure precisely. Both these problems have now been better addressed, although fairly late in comparison to the other hard sciences. With this knowledge, we can place the biological disciplines into modern and classical philosophies. The neo-Darwinian disciplines, such as genetics and molecular biology represent the new fields of biology, and the taxonomic and descriptive fields are representative of the classical biological fields of study.

The comparative fields of biology merge together both the modern Darwinian philosophy, with the classic platonic philosophy. As Dr. Chivers points out himself, citing Plato in Gordon et al. 1972, Plato clearly understood the limitations of his philosophy; "A cautious man should above all be on his guard for resemblances: they are a very slippery sort of thing". (1)

The comparative fields of biology have then, a tenancy to classify (i.e. group) characteristics, and discuss their similarities and differences, together with study of their adaptive functions. These two philosophies are at odds with each other as Stephen Jay Gould points out in his book 'Life's Grandeur' (2). The platonic philosophy presumes to create abstract concepts, or ideal models, and then fit real characteristics into these abstractions, with poor fits presumed to be badly fitting, or somehow non-ideal or in error. In contrast, Darwinian philosophy has no problem with dealing in and accepting variety as the normal. Gould (p. 40, op. cit.) states that "we are still suffering from a legacy as old as Plato, a tenancy to abstract a single ideal or averages the "essence" of a system, and to devalue or ignore variation. . ." and that "[I]n Darwin's post-Platonic world, variation stands as the fundamental reality and calculated averages become abstractions."

To summarise then, attempts to classify things according to idealised and abstract categories, such as dietary niches (e.g. "omnivorism"), are an ill conceived approach to achieving greater understanding of the biological realities. We must accept that any fit to such abstract groupings satisfies our desire to classify, rather than to explain. The practical ramifications become very serious when we realise that many species can be classified together, but their diets are wholly inappropriate for each other. For example, both koalas and cattle are strict herbivores, but their diets are unsuitable for each other. On the other hand rabbits and cattle are both herbivores with more compatible diets. Such apparently contradictory variation is wholly acceptable to Darwinian philosophy, but looks confusing with the platonic ideological system. When classifying digestive/dietary adaptations, we need to be sure that these are based on actual observations of feeding patterns and material eaten, and not upon purely abstract concepts - we want the numbers. We must ensure that taxonomic grouping is accurately reflective of diet. In addition we must also not repeat the same classification errors when dealing with food groups. We must also remember that one particular anatomical form can serve many different functions across species.

These platonic limitations have been identified and discussed extensively by Chivers et al., in "The Digestive System In Mammals" , and also earlier in "Food Acquisition And Processing In Primates"(3). Indeed, it is recognition of these problems that has inspired these scientists to develop comparative physiology towards an acceptable scientific discipline.

"Categorizing always includes a great danger because it can narrow thoughts and neglect the view to the basis of data used and required for the categories."
Paul Winkler, Food Acquisition And Processing In Primates, p. 161

What about "Omnivorism"

In both the works of Chivers, previously cited, his views on the old dietary category of "omnivorism" are clearly expressed along with his reasons. These are based upon material facts. He states that:

"[B]ecause, for anatomical and physiological reasons, no mammal can exploit large amounts of both animal matter and leaves, the widely used term 'omnivore' is singularly inappropriate, even for primates. Humans might reasonably be called omnivores, however, as a result of food processing and cookery." (4)

Chivers et al. also present graphical presentations of primate diets that make it quite clear that primates are not broadly generalised feeders such as the term "omnivore" suggests. They either prefer to eat fruits and animal matter in the case of smaller primates, or mainly fruit and leaf matter in the case of larger primates. The term omnivore is not really acceptable in this scientific debate, because it is not dietarily descriptive. This is clearly the view of authoritative scientists in the field of primatology, because they frequently place double quotation marks around the term omnivore when it is used. In this way they are reflecting the extra-scientific use of the term. It seems that the terms was probably coined before any useful analysis of diet had been made, because as Chivers says (The Digestive System In Mammals p.4); "The concept of omnivory is weakened by the anatomical and physiological difficulties of digesting significant quantities of animal matter and fruit and leaves." In short, omnivorism is biologically impossible to do effectively under natural conditions -- only the food processing techniques of man have created such possibilities.

Although some of Chivers own research points towards human gut morphology as being comparable to that of a faunivorous species, he is not so bold as to actually state that humans are faunivores.

It is clear that his findings are inconclusive as he states in 'The Cambridge Encyclopedia Of Human Evolution' (4), "Humans are on the inner edge of the faunivore cluster, showing the distinctive adaptations of their guts for meat-eating, or for some other rapidly digested foods, in contrast to the frugivorous apes". This statement suggests that the anatomical form or the digestive system reflects the properties of the food, and not its biological origin. While it is clear that the human digestive system differs anatomically to those of other frugivorous primates, it is accepted that the adaptation is for rapidly digested food, which may be flesh, OR some other rapidly digested foods. We must therefore have more anatomical evidence to support the hypothesis of humans having a flesh eating adaptation. Furthermore, humans are on the edge of the faunivore grouping, and not the centre, so the result is all the more contestable.

Of course, measuring and comparing the different surface areas of parts of the digestive system is only one way of comparing dietary adaptations. One needs also to consider the structure of the digestive system, to look at the teeth, and also the chemistry of digestion.

Let us now look at that classic bone of contention that proud meat-eaters point to, the human canine tooth. According to Glenn C. Conroy in 'Primate Evolution', page 380 to 381, ape and human teeth and mouths are distinctly different. Apes have a rectangular dental arch shape, while humans have a parabolic shape, but perhaps more significantly humans have "Incisiform" canines, whereas ape canines are described as "Stout, large, projecting". Indeed, incisiform canine teeth like the humans, are totally unique amongst higher primates. Enlarged spatulate incisors are recognised as an adaptation for tough foods and to fruit eating. Humans are not the same as apes, but just like them in so many ways.

If we accept the suggestion that humans evolved from some ape-like proto human ancestor with large protruding canines, that were probably pointed, we must ask what diet promoted the development of the well enamelled incisiform canine to mimic that of the other incisors, even though the underlying dentine structure is still pointy? An additional incisor would be most advantageous to a fruit-eating primate, one that must have so depended on fruit consumption, that even the small addition of an extra pseudo-incisor conferred a selective advantage. This dependence may have been because the proto hominid had a diet based highly, or perhaps wholly on fruit (or fruit like food), or because at some critical time, only fruits were available to eat for much of the preceding period.

Boselaphus (Bovidae) incisiform canine

Other animals having incisiform canines include sheep, elk, bison, caribou and cattle, where they use them to deal with fibrous vegetation. Amongst primates, incisiform canines are found in Lemurs, the larger of which eat herbivore-frugivore diets, although some species do include insects. By omitting crucial anatomical evidence of humanities frugivorous specialisations, it becomes easier to believe incorrectly, in an "omnivore" adaptation. The earliest hominid to have a canine that is between the primitive ape form, and the incisiform modern human form is Ardipithecus ramidis. This animal, which may have lived some 5 million years ago, is claimed to have a skull with features similar to a chimp, but teeth more like a human.

The term "omnivore" is in fact a misnomer, as Suzanne Ripley reports in her chapter of 'Food Acquisition And Processing In Primates', page 33;

"Insofar as frugivores must look beyond fruits (their energy source) to animals or leaves for protein, they are generalised feeders, sometimes called "omnivores", albeit inaccurately, (Chivers and Hladick, 1980)."

Ripley omits to mention nuts and seeds as potential primate protein sources.

Furthermore, we must remind ourselves that the above rules may not apply to humans who are different from other primates, so that the generalisations made about frugivores may not apply to us. We must be reminded that variation is the rule in evolution. No other primate uses bipedal locomotion as much as humans do, but it is absurd to suggest that we are somehow incorrect to walk bipedally. Ripley (op. cit.) also categorises strictly frugivorous monkeys, partly carnivorous chimpanzees and hunter-gatherer humans, under the single banner of "frugivores". (p.40)

Ripley classes hominids as "Frugivore-macrofaunivores", and alleges that our increase in body size over that of other primate frugivores is possible because of the inclusion of animal matter in the diet. This is quite possible, but there may be other explanations. For example, on page 54 (op. cit.) she suggests that chimpanzees achieved an increase in body size by utilising "hard-shelled" nuts in addition to termites -- insectivorous primates are smaller than chimpanzees. Plant, as well as animal foods, can provide abundant levels of fats and proteins.

Greater protein and fat intake can be achieved without using animal matter in the diet, by including young leaves or seeds, and these may be in the fruit, or as separate items such as sprouts, nuts or grains. Sweet leguminous fruits also yield sufficient protein content to satisfy human requirements. In addition, without taking relative rates of digestion into account, comparison by nutritional content alone is misleading. Human requirements for protein and lipids are in any case easy to meet on a plant based diet - there is no shortage of people now, who only eat plant foods.

Do all primates eat animal matter?

The answer may be yes, and this may even be true for all mammals (humans included), because it is virtually impossible, even with food processing technology to remove insect matter from natural food sources. Even sleeping humans who breathe through their mouths probably ingest impressive numbers of bed lice. But this line of debate risks entering into the reductio ad absurdum posturing. Clearly any meaningful debate on the issue needs to identify at what level of ingestion, insect matter is a useful part of the diet, and at what level it is insignificant. In addition, the presence of parasitic or symbiotic animal life in digestive system also means that many mammals are receiving some "animal" form of nutrition.

Unless sprayed, most grain foods will contain some weevils, in addition small mammals fall into the harvesting equipment or are killed in stores or processing plants, and thus very small amounts of animal matter are found even in bread, and probably more so if the grain is more naturally produced. Even so, people who eat these foods can still claim to be "vegetarian", though it is inaccurate to suggest that such a the diet is free of all animal tissue. The point is that they did not intend to eat the animal matter, and it was not practical to remove it. The same might be said of gorillas and their diets, although we might suggest that they are not motivated by intent to avoid eating animals, but rather they have no intention to do otherwise.

Vegetarians have been criticised for abusing scientific sources in claiming that the gorillas a vegetarian. But what else are we to make of statements such as "The gorilla is a strict vegetarian. . ." from Bradley, 1922, quoted in 'Apes of the World', page 55. And what of Yerkes and Yerkes (1929) conclusion that "apes are primarily vegetarians" (5). Of course such statements fired up the vegetarian agenda.

What else does Tuttle have to say in his extensive review of primate literature on diet?

Orangutans have been widely observed to eat insects and sometimes carrion, but: "MacKinnon (1971, 1974a) never saw wild orangutans drink from streams or eat vertebrate prey. He found no hair, feathers or bones in their feces" (p. 66), "Vertebrate remains were not found in any of the fecal samples (Rijksen, 1978)" (p.69), ". . . the only report of meat-eating by wild Pongo pygmaeus is that of a consorting young Ketambe female" (p.74).

Common chimpanzees are now also known to hunt and even engage in the cannibalistic feeding on their infants. This by no means proves that all chimp groups have engaged in this behaviour, or that it is nutritionally essential. The following findings have been less well reported: According to Tuttle, the first substantive information on chimp diets was provided by Nissen in 1931 (p.75). In 1930 Nissen spent 75 days of a 3-month period tracking and observing chimps. He made direct unquantified observations and examined fecal deposits and leftovers at feeding sites. He also found "no evidence that they ate honey, eggs or animal prey" - this observation may have been too limited due to seasonal variations in chimp die.

In Reynolds and Reynolds (1965), Tuttle says that a 300 hour study of Budongo Forest chimps over an 8-month period revealed "no evidence for avian eggs, termites or vertebrates", although they thought that insects formed 1% of their diet (p.81). In another study of Budongo Forest chimps from 1966 to 1967, Sugiyama did not observe "meat-eating or deliberate captures of arthropods", although he reported that "the chimpanzees did ingest small insects that infested figs" (p.82).

Tuttle says that later observations at Budongo by Suzuki revealed meat eating. Where the earlier observations wrong, or incomplete, or maybe an accurate reflection of their diet at the time? Did the chimps change their diet later? We do not know. Chimps sometimes change their diets on a monthly basis. A study of chimps at the Kabogo Point region from 1961 to 1962 by Azuma and Toyoshima, revealed that they witnessed "only one instance of chimpanzees ingesting animal food, vis. termites or beetles from rotten wood." (p.87). From 1963 to 1964, similar observations were found in Kasakati Basin by a Kyoto University team, and when Izawa and Itani published in 1966 they reported "no chimpanzees eating insects, vertebrates, avian eggs, soil or tree leaves and found no trace in the 14 stools that they inspected " (p.86). In contrast Kawabe and Suzuki found the Kasakati chimps hunting in the same year (p.88), although only 14 of 174 fecal samples contained traces of insects and other animal foods. So perhaps these differing observations are due to seasonal variation, or even local differences (cultural variation) in feeding preferences - Tuttle does not reveal which. Maybe some of the chimps groups are 'vegetarian', while other are not. But see the Kortlandt observations below before believing that all chimps are meat-eaters.

Far less is known about bonobo feeding habits than about the common chimpanzee. Like chimps, the bonobo is also known to eat insects and carrion, although unlike chimps it has not been observed to hunt. Kano and Mulavwa provided the most detailed account of the feeding behaviour of Wamba bonobos based on a 4-month study. Tuttle reports that their diet was 80% fruit pulp, 15% fibrous foods and 5% seeds, and that "Animal foods constituted a minute part of their fare" (p.95).

The best evidence, if there is any, of a "vegetarian" ape is the gorilla. As with the other apes, there is great variation in what gorillas eat based on their locality, and season. A 15-month study of gorillas at Campo by Calvert, is reported by Tuttle (p.100), in which he says that out of 280 stools, 1 example of stomach contents and 1400 feeding sites, plus direct observations, there was "no evidence" that "Campo gorillas ingested animal matter." Similarly, Casimir and Butenandt followed a group about 20 gorillas at Kahuzi during 15 months in 1971 to 1972 (Tuttle, ibid., p.102). They collected 43 fecal samples at fairly regular intervals but none "contained remains of vertebrates or invertebrates". In addition, the gorillas did not disturb active birds and honeybee nests that were clearly visible near their own nests. Nor did they unearth bee nests. Goodall also noted that Kahuzi gorillas ignored eggs and fledglings and did not invade bees nests (Tuttle, ibid., p.105), and that none of the many fecal samples he found contained animal remnants. Tuttle also reports that the "most detailed" study of 10 groups of Zairean Virunga mountain gorillas by Schaller in 13 months from 1956 to 1960, including fecal samples and 466 direct hours of observation, found "no evidence that they raided apian nests, which were common at Kabara, ingested animal foods, or drank water." (p.107) In 1959, a 64-day study by Kawai and Mizuhara of gorillas at Mts. Muhavura and Gahinga also found "no evidence for animal foods in the gorillas' fare." (p.108)

The story for gorillas is by no means a clear one, as findings seem to vary from one study to another. You can pick them to suit your agenda. For example, Adriaan Kortlandt says in 'Food Acquisition And Processing In Primates', page 133-135, that "Gorillas have never been observed to eat honey, eggs, insects or meat, not even when they were sitting or nesting almost on top of honeycomb or a bird's nest, except for one single case of honey-eating reported by Sabater-Pi (1960)" He adds however, that Fossey (1974) reports that slugs, larvae and worms were found to constitute 1% of the food item observations recorded. Kortlandt adds that "No animal remains have been found in gorilla dung, except for one case presumably indicating cannibalism (Fossey, 1981)."

In Noel Rowes colourful book 'The Pictorial Guide To The Living Primates' there are a total of 13 primate species listed as eating no animal matter. These are:

  1. Callithrix kuhlii
  2. Callicebus personatus
  3. Hapalemur aureus
  4. Lemur catta
  5. Chiropotes albinasus
  6. Chiropotes satanas
  7. Procolobus verus
  8. Trachypithecus cristatus
  9. Aloatta seniculus
  10. Trachypithecus vetulus
  11. Aloatta palliata
  12. Hylobates concolor
  13. Ateles belzebuth

Species listed as eating less than 1% of their diet as animal matter include the following species:

  1. Gorilla gorilla beringei, 0.1%
  2. Pithecia albicans, 0.4%
  3. Callithrix humeralifer, 0.5%
  4. Pithecia pithecia, 0.8%

If primates do eat animal matter, why?

It is not enough to argumentum ad Novitatem, state that later differing observations disprove earlier observations -- this is concerning in a laboratory setting where all external variables are controlled. Differences in behaviour patterns may arise swiftly, or may vary geographically -- older findings may be perfectly valid. The use of predation in Old World monkeys is also discussed and it seems that this is "primarily an emergency measure for special needs (Kortlandt and Kooij, 1963)." In support of the idea that the eating of animal products is a response to environmental stress, he sites some of his findings and those of Jane Goodall (from personal communications) stating that in nine tests, when groups compromising on average 9.4 apes passed by a total of 16 times and noticed some hens eggs, placed in dummy birds nests, only six times (38%) did an individual take away and probably eat an egg, and these eggs were presumed to only have been eaten by 3 individuals. However, in the harsher environment at Gombe, Goodhall observed that 60% of the chimpanzees ate the hen's eggs at the camp-site.

Kortlandt states that predation by chimpanzees on vertebrates is undoubtedly a rather rare phenomenon among rainforest-dwelling populations of chimpanzees. Kortlandt lists the reasons given below in his evidence.

Kortlandt concludes this section on primate diets by saying that the wealth of flora and insect fauna in the rain-forest provides both chimpanzees and orang-utans with a dietary spectrum that seems wide enough to meet their nutritional requirements, without hunting and killing of vertebrates being necessary. It is in the poorer nutritional environments, where plant sources may be scarce or of low quality where carnivorous behaviour arises. Even then he says that the meat obtained are minimal and perhaps insufficient to meet basic needs. Finally he adds "The same conclusion applies, of course, to hominids . . . it is strange that most palaeoanthropologists have never been willing to accept the elementary facts on this matter that have emerged from both nutritional science and primate research."

So it appears that chimps, and perhaps hominids, have resorted to eating meat because no suitable plant food was available. Interestingly Kortlandt cites old findings of renowned German zoologist Reichenow, who published an article in 1920, relating how wild chimpanzees and gorillas had possibly symbiotic ciliates that live mainly in the hindguts, but the majority of which were digested by the host. After the apes had been kept for a while, these ciliates died off and the primates developed digestive disorders. Furthermore "newly captured apes showed "disgust" (Abscheu) when offered meat, but after habituation they learned to eagerly eat large quantities of it." Reichenow inferred that the symbiotic function of these ciliates may be to convert vegetable food into what he named "animal food for a vegetarian that requires nutrients of animal origin".

The Paleopoetry Diet

Science is a wonderful tool at helping us to explore and understand nature. It is however, only one way of approaching an understanding of ourselves, and at 'Beyond Veg' we see the classical error of reification - where sciences abstract taxonomic constructs are held to reflect a concrete biological reality. While it is quite reasonable to order fossil finds or existing species into parsimonious patterns of similarity and perceived change through time, it is a great error to think that these organisations are reflective of our actual ancestry, or indeed that the fossils found are our actual ancestors (although they might be!).

Recent analysis of plant DNA has better enabled the relationships between plant species to be identified. As a result of this, the taxa have had to be changed because the phenotype information used to class the plants did not reflect their genetic relatedness. If the taxonomy of existing organisms, which we examine every aspect of, is still misleading us as to biological relatedness, then what hope have we for reliably relating organisms for which we only have fossil fragments and no DNA?

According to 'Beyond Veg' all the paleontologists evidence indicates that human ancestors were "omnivores". But how much scientific weight should we apply to what paleontologists say? According to Richard Lewontin (6), in his book 'It Ain't Necessarily So', we can only be sure a fossil is really a human ancestor if it is already "indubitably" human, but then it has no interest. Furthermore he says that "The further back in time one goes and the greater the differences from us, the more likely it is that the bones belong to some twenty-second cousin twelve times removed." (p.59) As each new fossil find is incorporated into the evolutionary tree, the tree becomes more complex, and the simple linear view of our alleged ancestry that is presented, has to be adjusted. Lewontin says that "most fossils of different ages cannot be connected in a linear sequence, but represent a small sample from a lot of parallel lines."

While paleontology offers us a glimpse into what human evolution may have been like, it does not give us anything like a conclusive, or even an accurate picture. At its best, such evidence may only serve as crude, and perhaps sometimes misleading guide as to what actually happened. Some people are seduced into feeling that paleontology offers us an accurate history. This belief is fuelled by a desire to know their past, more than by scientific fact.

The fossil record can be assembled to conform to what we would expect from the concept of evolutionary theory, but it does not describe the evolution that actually happened - that would be an error of reification.


This article has clearly demonstrated numerous gross and glaring errors in the 'Beyond Veg' material, errors of logic and in philosophy. It has proven that the author does not understand evolution, and that by omission, a distorted view of the available scientific evidence has been produced. It has shown how the authors incorrectly report scientific observations, and draw invalid deductions, and how they refuse to concede that humans are frugivores. Sufficient evidence has been produced to demonstrate that some gorilla groups are accurately described as "vegetarian", and also that some chimp groups may not have been meat-eaters. Similarly, many primates have been identified that are not known to ingest animal matter.


  1. D. J. Chivers, P. Langer, The Digestive System In Mammals: Food Form And Function, Camb. Uni. Press, 1994, p.25
  2. S. J. Gould, Life's Grandeur: The spread of excellence from Plato to Darwin, Vintage,1992
  3. D. J. Chivers et al., Food Acquisition And Processing In Primates, Plenum Press, NY 1984
  4. The Cambridge Encyclopedia Of Human Evolution, Jones, Martin and Pilbeam, Camb. Uni. Press, 1992
  5. R. H. Tuttle, Apes of the World; Their Social Behaviour Communication, Mentality and Ecology, 1986
  6. R. Lewontin, It Ain't Necessarily So, Granta, 2000

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