Short people known as pygmies are scattered across equatorial Africa, where they speak various languages, inhabit different types of forests, and hunt and gather food in diverse ways. Despite their cultural variety, a new study shows that the pygmies of Western Central Africa descended from an ancestral population that survived intact until 2800 years ago when farmers invaded the pygmies' territory and split them apart.
The origins of pygmies have long been a mystery. Researchers have debated whether African pygmies inherited their height from a common ancestor they shared long ago or whether shortness evolved independently in each tribe because it was advantageous for life in the forest. For instance, getting enough calories to grow taller might have been more challenging than in more open terrain. Pygmies grow up just like other modern humans until they become teenagers, when they fail to undergo a final adolescent growth spurt.
Although humans have lived in the forests of Western Central Africa for at least 30,000 years, there are no fossils to show whether the ancestral population was short to begin with--or whether the trait evolved more recently in different groups. Previous DNA studies haven't resolved the question.