Gatherers Part 2

Adaptation to a specific vegetarian diet means that the animal becomes entirely dependent on certain vegetable species. That is exactly what happened to the lemurs on the island of Madagascar, just 400 kilometres from the south-east coast of Africa.
  The lemurs are in reality ancient primates, very similar to the  ancestor which would later gave rise to all the different monkeys; they are, therefore, called proto-simians.
  The lemurs became isolated in Madagascar before this happened, and, unlike everywhere else on the planet, were saved from extinction there. 
  In this way, the lemurs followed their parallel evolution and adapted to the different habitats and plant foods of the island. Today, 33 species of lemur survive, so totally specialised that almost all depend on the bush   and tree species on which they feed, which grow only in Madagascar. They could not, therefore, live anywhere else, even if they wanted to.

With all the characteristics of a jungle-dwelling, fruit-eating primate, including the most efficient brain on the planet, humans took gathering to limits never before reached by any animal.

In the same way as these Australian Aborigines still do today, humans became great specialists, adapted to different types of food. So, if a given resource became scarce, this was immediately compensated for by the abundance of another. 

Bushmen are hunter-gatherers. Physiologically, they are different from other human groups, because they are adapted to the des their dark yellowish skin has a wrinkled appearance, due to the fact they do not have subcutaneous fat. 80% of their diet is vegetable: they gather around 100 different species of   roots, bulbs and nuts. Anthropological studies have demonstrated that this diet is surprisingly rich and complete, and that it gives the Bushmen long life with almost no symptoms of anxiety or insecurity.