Bellies don’t shrink for big brains

Swiss scientists have discovered that developing a bigger brain does not mean making do with a smaller stomach and intestinal tract as was previously thought.

Their study, which will appear in Nature magazine, has debunked the assumption that humans were able to grow large brains after they began eating meat and cooking their food, which eased digestion.

The human brain accounts for just two per cent of a person’s weight, yet uses nearly 20 per cent of the body’s available energy. In comparison, a chimpanzee brain is just a third of the size of a human one.

A team of anthropologists from Zurich University dissected 100 mammals to compare the sizes of their brains in proportion to their digestive tracts.

They concluded that animals with large brains do not have smaller digestive tracks than those with larger brains. They also found that the more fat an animal’s body is able to store, the smaller its brain tends to be.

It seems that animals can either store fat or use their wits to survive during periods when there is little food available.

Yet humans, whales and seals are the exception. They are relatively fat and still have highly developed brains.