Replica of a Homo habilis skull found in Koobi Fora, Kenya by Kamoya Kimeu in 1973, and estimated to be 1.9 million years old. H. habilis is one of several extinct hominin species that form an early part of the human evolutionary tree. It lived between 2 and 1.6 million years ago in East Africa during the Pleistocene. It had a brain size just less than half that of modern humans. The name Homo habilis means 'handy man', adopted because the species used primitive stone tools. Photographed at CosmoCaixa Science Museum, Barcelona, Spain.