It has passed into popular folklore that chimps have been observed eating meat, which has been taken as an indication that humans too have evolved to eat meat. This is in large part due to a David Attenborough film many years ago in which chimps were seen hunting small monkeys and baby bushpigs. Attenborough’s observations were first recorded by chimpanzee expert Jane Goodall. Her group of chimpanzees was studied over a period of years so the amount of meat eaten and the number of animals killed could be exactly recorded. Over a span of 10 years, the 50 or so chimpanzees killed and ate 95 mammals. They were all tiny – the young of bushpigs, bushbuck and baboons – and most weighed 10lbs or less. It works out at 2.4 grams per individual per day – about the size of a pea! But even this may be an overestimate caused by observer disturbance in the chimp populations studied. So, meat-eating in chimps is actually incredibly rare – rough estimates are that it forms just 1-1.5 per cent of the overall diet. And, of course, not all chimp groups hunt at all.
Whilst our primate ancestors did eat insects this was not in sufficient quantity to provoke a change in their dentition. Primate canine teeth are small and their molars have a large grinding surface with a thick enamel covering, making their jaws a powerful crushing, grinding and chewing machine designed to cope with vegetation.
Of all the living primates, humans are the only one to eat large animals, the rest being almost entirely herbivorous. We sprang out of this genetic breeding pool of largely peaceful groups of amiable creatures that lived by eating grasses, leaves, nuts, berries, fruits and roots. There can be no doubt that our metabolism, built up through these millions of years, is best sustained by a vegan and then a vegetarian diet, in that order.