LIFE on our planet is a complex, interwoven web. As humans, we cannot survive alone by ourselves. Like all living creatures, our Palaeolithic ancestors required warmth, water, shelter and other basic requirements of existence.
In particular, survival depended very significantly on acquiring energy (in the form of proteins, fats and carbohydrates) and nutrients from other species of animals and plants. There is considerable evidence to suggest that our brains and intelligence had originally evolved to better adapt to the tasks of acquiring such prerequisites of Palaeolithic life.