A new study found that 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.
Researchers at the Universities of Cambridge and Tübingen (Germany) 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).
Their analysis showed that early humans ranged from 4 feet 8 inches to almost six feet tall.
"What we're seeing is perhaps the beginning of a unique characteristic of our own species - the origins of diversity," Jay Stock, co-author of the study from the University of Cambridge's Department of Archaeology and Anthropology. "It's possible to interpret our findings as showing that there were either multiple species of early human, such as Homo habilis, Homo ergaster and Homo rudolfensis, or one highly diverse species. This fits well with recent cranial evidence for tremendous diversity among early members of the genus Homo."
"If someone asked you 'are modern humans 6 foot tall and 70kg?' you'd say 'well some are, but many people aren't,' and what we're starting to show is that this diversification happened really early in human evolution," he added.
The variations also seem to be regional. For instance, early humans who lived in South African caves stood 4' 8" tall while those from Kenya's Koobi For were 6 foot tall.
"In human evolution we see body size as one of the most important characteristics, and from examining these 'scrappier' fossils we can get a much better sense of when and where human body size diversity arose. Before 1.7 million years ago our ancestors were seldom over 5 foot tall or particularly heavy in body mass."
The study was published in the March 27 issue of the Journal of Human Evolution.
