We eat anything
Sir: If GCSE biology teaches that our digestive systems are similar to those of carnivores (letter, 22 June), then it is wrong; our intestines are far too long for that, not to mention our feeble teeth and non-existent claws. Nor, obviously, are we foliage eaters
Our ancestors evolved to feed mainly on fruits and nuts, which do not need grinding teeth or fermenting chambers. Our recent ancestors adopted the strategy of omnivory, which is rare because of the risk of poisoning that it carries. We, like a few other highly social species such as pigs and rats, have developed reasonably reliable ways of warning each other off toxic foods. With fire and tools, hominids also long since learned to use foods that we could not eat raw.
We must now use our omnivory to adjust to new diets that will bear less heavily on the biosphere. Meat-eating was a viable strategy as long as there were only a few hundred million people in the world. Now that we number six billion it spells disaster.
P J STEWART
St Anne's College, Oxford