San Diego Museum of Man - Footsteps Through Time

Timestone 11
1.8 to 1.5 million years ago
Homo ergaster

A new species evolved in Africa about 1.8 million years ago. This hominid was possibly a descendent of Homo habilis and lived at the same time as some australopithecines.

This skull was part of a nearly complete (about 80%) skeleton, the earliest Homo ergaster ever found and one of the most complete hominid skeletons. Compared to earlier hominids, this fossil showed a larger cranial capacity (indicating brain size), smaller face and grinding teeth, more of a nasal bridge, and thicker skull bones.

Sculptural replica of fossil skull
Homo ergaster-Turkana Boy

A skull fragment found in West Turkana, Kenya, in Africa, in 1984 by Kamoya Kimeu. Remaining bones recovered and analyzed by Alan Walker and Richard Leakey over the next three years.
Age: 1.6 million years

Turkana Boy" Reconstruction
Artist: John Gurche

Turkana Boy was between 8 and 11 years old-scientists can tell from his teeth. Judging by the shape of his pelvis and the size of other bones, he was male. His epiphyses (ends of long bones) were not fully developed, so he still had some growing to do. He was about 5 feet 4 inches (1.6 m) tall when he died. If he had lived to adulthood, he would have grown to be 6 feet (1.8 m) tall. He represents the tallest hominid species found until modern Homo sapiens. Turkana Boy lived in a warm climate very much like that of today's East Africa where he was found.

Migration: From Africa to Asia.

Homo ergaster evolved in Africa, but by one million years ago Homo species lived in Asia and possibly Europe. The species in Asia is called Homo erectus. This is the earliest hominid found living outside Africa. One beneficial adaptation may have been a larger nose, with circulation that helped reduce water loss in warm climates and conserve heat in colder regions.