![]() ![]() John Hawks of the University of Wisconsin-Madison says the similarities between A. “This study is really interesting because it shows how the hand was actually used, and that’s consistent with stone tool use,” says McPherron. This revealed that their owners had been tree swingers but had also spent a lot of energy tightly pinching small objects, suggesting they were indeed early tool users. When Skinner and his colleagues looked at the metacarpals of early human species and neanderthals – who also used stone flakes for tasks like scraping and butchering – they found bone ends that were shaped like modern human bones, and unlike ape bones.įinally, they looked at metacarpals from four Australopithecus africanus individuals, up to 3 million years old. This precision squeeze between thumb and fingers is uniquely human and a legacy from our flint-wielding ancestors. Most of our activities involve some kind of pinching – think of how you hold a pencil or pick up a cup. Modern human metacarpals looked different because we use our hands differently. Bottom row: CT scans of the same specimens, showing the structure inside (Image: T.L. Top row: a selection of metacarpal bones. Skinner and his colleagues predicted how this should shape the soft bone in ape hands, then looked at modern ape bones, finding their predictions were right. ![]() ![]() That exerts a great deal of force on the joints in its hands, in a specific way. Because the bone ends are made of soft, spongy bone tissue, they are shaped over a lifetime of use and moulded by what that hand has done.Ī chimp, for instance, spends a lot of time swinging from branches and knuckle-walking. Specifically, they looked at metacarpal bones – the five bones in the palm of the hand that articulate the fingers. They decided to look at the hands that held them. Matthew Skinner at the University of Kent in the UK and his colleagues have now found something they think is as exciting as finding an earlier tool. ![]()
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