Scratches on an ancient tooth hint that Homo habilis was right-handed
The teeth of one Homo habilis fossil, OH 65, carry scratches slanting to the right. One explanation: the individual gripped meat in its teeth and left hand while slicing with a stone tool in the right, occasionally nicking enamel. If so, it suggests right-handedness and a brain already dividing its labour between hemispheres.
Handy man lived in East and South Africa from about 2.4 to 1.65 million years ago, among the oldest archaic humans known; a jawbone found in 2015 prompted suggestions to push its origin back to 2.8 million years. Its brain ranged from roughly 500 to 900 cubic centimetres, its tooth rows were V-shaped, and its lower face jutted forward while the upper face stayed flat.
The discovery story has overlooked heroes. Jonathan Leakey's team found the partial juvenile skull and hand bones of OH 7 at Olduvai Gorge, Tanzania, in 1960, dated to 1.75 million years ago. But the first remains were a molar, OH 4, found in 1959 by Heselon Mukiri, senior assistant to Louis and Mary Leakey, though nobody realised it then. In 1964 Louis Leakey, Phillip V. Tobias and John R. Napier placed the fossils in Homo, and Raymond Dart suggested the name habilis, Latin for able or handy. Its link to Oldowan tools, then taken as a sign of advanced thinking, helped justify the genus.
The classification has been fought over ever since. Critics first wanted it folded into Australopithecus africanus, partly because Homo was then assumed to have arisen in Asia and the brain fell below the threshold Wilfrid Le Gros Clark proposed in 1955. When Tim D. White found the fragmentary skeleton OH 62 in 1986, its body looked more australopithecine than human, and in 1999 Bernard Wood and Mark Collard proposed moving the species to Australopithecus. Later reassessments of OH 62 as more humanlike would weaken that case.
Homo habilis made Oldowan stone tools, mostly for butchery, and probably scavenged much of its meat. If its groups resembled those of savanna chimpanzees and baboons, they may have held 70 to 85 members, with several males helping fend off big cats, hyenas and crocodiles. It shared the landscape with Homo erectus, Homo rudolfensis and Paranthropus boisei.
Source: Homo habilis
