10 Extinct Hominids

Homo Ergaster
"Turkana Boy" is the most complete example of the Homo ergaster species. His skeleton reveals that he walked upright and reached the height of modern humans. Tony Karumba/AFP/Getty Images

In 1984, archaeologists discovered a striking example of Homo ergaster in the skeleton known as "Turkana Boy" (after having been found in Turkana, Kenya). Before, all we had to tell us about ergaster was a lower jaw, but Turkana Boy is a nearly complete skeleton, revealing much more. He had a narrow pelvis that indicates he was very comfortable walking upright on two feet. His arms were shorter and his legs were longer than his predecessors.

What's perhaps most striking is how tall Turkana Boy was. Although he was likely not fully grown, he grew to 5.25 feet tall (1.6 meters) before he died, meaning ergaster is the first of the genus Homo we know of that reached the height of modern humans [source: Roberts]. It is difficult to estimate the age of death for many hominid fossils because they also had different growth patterns and a shorter adolescence than modern humans, but judging from the teeth, experts believe Turkana boy was probably 8 or 9 years old [source: Smithsonian].

Other fossils have been found in Tanzania, Ethiopia and South Africa. Homo ergaster lived 1.9 million to 1.5 million years ago, and its name means "workman," stemming from the fact that the species made tools from stone, such as the Archeulean handaxe. This was a hand-held stone tool that was forged from striking flakes off to form a sharp edge, possibly used for butchery or chopping wood.

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