About 920,000 pygmies live, threatened by deforestation and forced displacement, in scattered communities – aka, efé, mbuti, batwa, baka – throughout nine countries in central Africa. They are characterized by their short stature – men measure around 1.5 meters, and women, 1.45 -, their short life expectancy – between 17 and 24 years – and their genetic divergence. These archaic populations, dedicated to hunting and gathering, would have separated from the common African trunk about 70,000 years ago and adapted to extreme living conditions.
One theory attributed their small size to a poor diet , but Turkanas and Msai reach considerable heights and are also exposed to a poor diet. A few years ago, a study from the University of Pennsylvania pointed out that the height of pygmies would have a genetic basis linked to their early reproductive maturity and their resistance to infectious diseases. The genetic pressure to leave offspring would have affected their size.
Another later work, also from this University, defended that natural selection would have made the pygmy phenotype evolve to give its bearer advantages in a jungle, hot and humid environment, and make his organism save energy. The short stature allows less stooping in the dense forest and gives greater freedom of movement.
