Homo habilis

by
Janet Russell
Scientist

Long Foreground - Species Timeline - Homo habilis - 1

Homo habilis: The first human species

Homo habilis is the earliest known species of the genus Homo; that is, the first human species. It existed from approximately 2.2 to 1.6 million years ago in east Africa.

Only a few fossil remains have been discovered so far, but these specimens exhibit a clear trend toward larger brain size. H. habilis brains are about 30% larger than those of A. africanus. Males were much larger than females, as shown by the two skulls at far right. The male is pictured on the left. Sexual dimorphism in early Hominid species expressed itself in significant size differences.

The reconstructed skull pictured above was found in 1972 on the shores of Lake Turkana and represents the oldest individual human yet discovered. The background of the photo shows the kind of environment in which this earliest-known human species lived--open bush and savannah country in east Africa. This must must have been a very challenging environment, filled with large predators.

Homo habilis: The "handy man"

Homo habilis ("handy man") qualifies as a human almost solely by skeletal anatomy, which is quite like our own. Very little is known of its life or mental capabilities, athough the stone tools shown above are thought to have been fashioned by this species.

These crude hand axes and stone flakes could have been manufactured as needed or as opportunity arose. The fracture lines of stones create a sharp cutting surface capable of butchering fairly large animals. The photo above right shows a modern anthropologist skinning a calf with a stone tool made just as ancient Homo habilis would have done.

One widely held view of human development has held that hunting as an activity was the chief driver of evolutionary change in early humans, as it would have selected for for certain kinds of intelligence, coordination, and aggressive behavior [this is called the "Hunting Hypothesis"]. Was Homo habilis a hunter of large game and a successful competitor with the great predators of Africa--lions, leopards, hyenas? Or was this species an opportunistic taker of small game and a scavenger? Present evidence cannot answer the question, but a scavenging role seems more likely.

Homo habilis: Important archaeological sites

Homo habilis was first discovered in 1959 in the Olduvai Gorge in Tanzania. The nearly complete skull of H. habilis pictured here (inset) was discovered in 1972 at Koobi Fora on the shores of Lake Turkana in Kenya. Its age is estimated at 1.8 million years and its brain capacity at 800 cc. Other H. habilis remains have since been discovered at Olduvai Gorge.

There is considerable variation among the specimens from this era found thus far. Some anthropologists argue that the variations appear to indicate that several separate species of humans existed and competed at the same time in east Africa; other scientists lump all the individuals together in a single species.

Evidence Information

KEYWORDS	evolution
SUBMITTER	Janet Russell