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Saturday 3 December 2016

Chimps' hands more evolved than ours

science

Human hands may be less evolved than those of chimpanzees, research suggests.

The strongly-held notion that the human hand, with its long opposing thumb, was shaped by intelligent tool-making is misplaced, scientists believe.

Instead it is the chimpanzee whose hands have shown the biggest changes, evolving not to tap computer keyboards but to hang from branches.

Unlike chimps, but more like gorillas, human hands have long thumbs in relation to their index fingers.

This has been seen as one of the most distinctive traits of humankind and is often cited as one of the chief reasons for our success as a species.

Manipulate

A long opposing thumb makes it easier to pick up and manipulate objects with precision, and has been associated with the invention of stone tools.

But, according to the new evidence, the basic configuration of the human hand has changed little over time.

Anatomical analysis shows that thumb-to-finger ratio is much the same in very early humans, people living today and gorillas, suggesting a link with a dextrous common ancestor.

In contrast, chimps of the species family Pan, as well as orangutans, have grown elongated fingers ideally suited for life in the trees. The findings challenge the idea that a chimp-like hand was the starting point of evolutionary progress towards the modern human hand.

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