Fossils Show Size Variation in Early Humans, African Exodus Theory May be Revised

Ancient homo species varied in size as much as modern humans, new studies on fossil measurements have shown.

The findings of a study by researchers is significant as it questions the predominant notion on human evolution that larger bodies were precursors to early homo species moving out of Africa, to colonize Eurasia. The new study claims that the transition from smaller bodies to large bodies happened tens of thousands of years after Homo erectus left Africa, Daily Mail reports.

"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," said Jay Stock, the study's co-author.

Stock and co-author Manuel Will determined a range of body sizes for early human ancestors who lived between 2.5 million and 1.5 million years ago, using fossils found Kenya, Tanzania, South Africa, and Georgia. Given the scanty fossil record that made such measurements difficult in the past, the researchers developed a new method that helped them estimate size from bones as small as toes.

They found height variations ranging from 4.8 feet to 6 foot, just like modern humans.

Stock said that the first cracks in theory that long bodies evolved before migration, appeared with discovery of a Georgian fossil of a short-legged Homo erectus dating to 1.77 million years ago.

"The first clues came from the site of Dmanisi in Georgia where fossils of really small-bodied people date to 1.77 million years ago. This has been known for several years, but we now know that consistently larger body size evolved in Eastern Africa after 1.7 million years ago, in the Koobi Fora region of Kenya," Stock said.