Earliest known hand bone resembling those of modern humans found in Africa

There was a time long, long ago when our ancestors began to favor a completely terrestrial lifestyle, abandoning activities such as regularly climbing and swinging on trees. That appears to have happened much earlier than previously believed.

A 1.84-million-year-old lower pinky bone resembling those of people today was found in Tanzania. Researchers believe it came from a human of East African hominin roots. The bone predates what had been the oldest discovery of such by about 600,000 years.

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Among the largest difference in the hand structure of land and tree dwellers is the shape of the individual bones. Curved ones are formed by moving around via trees, but while they fit comfortably over branches, they also inhibit thehand's dexterity. Straight ones, however, can be more easily manipulated.

The discovery could add much needed insights into early hunting and stone tool-making practices.

Photo by M. Domínguez-Rodrigo

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