According to a new study, our ancestors came in different shapes and sizes as early as almost two million years ago. The study is the first to compare the body size of early humans who lived between 1.5 million and 2.5 million years ago.
The study, which was conducted by the researchers from the University of Tubingen and the University of Cambridge, shows that the primary increase in body size took place tens of thousands of years after Homo erectus departed Africa, and mostly in the Koobi Fora region of Kenya.
Manuel Will, researcher from the Department of Early Prehistory and Quaternary Ecology, University of Tubingen, and the lead author of the study, said, “The evolution of larger bodies and longer legs can thus no longer be assumed to be the main driving factor behind the earliest excursions of our genus to Eurasia.”
For their study, the researchers developed a method of calculating the height and body mass of early humans by using tiny fossil fragments. The team focused on three species that are known to have lived in Africa between 1.5 million years and 2.5 million years ago: Homo habilis, Homo rudolfensis and Homo ergaster (the working man).
They found considerable local variation in the size of early humans during the Pleistocene. They discovered that early humans ranged from 4 feet 8 inches to almost six feet tall.
Jay Stock, faculty member Archaeology and Anthropology Department, University of Cambridge, and one of the members of the study, said, “What we’re seeing is perhaps the beginning of a unique characteristic of our own species – the origins of diversity. Basically every textbook on human evolution gives the perspective that one lineage of humans evolved larger bodies before spreading beyond Africa. But the evidence for this story about our origins and the dispersal out of Africa just no longer really fits. We tend to simplify our interpretations because the fossil record is patchy and we have to explain it in some way. But revealing the diversity that exists is just as important as those broad, sweeping explanations.”
The findings were published in the Journal of Human Evolution.