Early Human Ancestors Were Just as Handy

It turns out that early human ancestors were just as handy as we are today, using human-like hand postures much earlier than scientists previously thought, a new study shows.

Approximately 3.2 million years ago, Australopithecus africanus seemed to be using stone tools with a similar dexterity to that of modern humans. For example, they possessed the distinctly human ability for forceful precision, such as when turning a key in a lock, and power "squeeze" gripping (like when using a hammer).

These particular abilities are linked to two evolutionary transitions in hand use: a reduction in arboreal climbing and the manufacture and use of stone tools.

This challenges the pre-conceived notion that Homo habilis, also known as "Handy Man," was the first maker of stone tools.

"Instead, I think our findings show that the traditional view that stone tool use was something that only members of our own genus Homo were capable of is outdated," senior author Tracy Kivell told Discovery News.

However, scientists still aren't sure exactly when pre-Homo humans became so handy. So to learn a bit more, a team from the University of Kent used new techniques to examine the internal spongy structure of bone called trabeculae. Trabecular bone remodels quickly during life, and so can reveal how fossil species used their hands during their lifetime.

First, the scientists compared the trabeculae of hand bones of humans and chimps. As predicted, they found distinct differences between humans, who have a unique ability for forceful precision gripping between thumb and fingers, and chimpanzees.

However, they were surprised when they found human-like trabecular bone patterns in the bones of the thumb and the palm of A. africanus, a species that scientists previously thought did not engage in habitual tool manufacture.

The findings, published in the journal Science, support recently discovered archaeological evidence for tool use in australopiths, and that early human ancestors were just as handy with tools.

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