About 2.5 million years ago, the global climate began to cool. “Origin of the Genus Homo,” asserts that this may have been the spark that caused an Australopithecus species to evolve into the first human species. The earliest known of these is Homo habilis, which lived from approximately 2.3 to 1.4 million years ago in East and South Africa. Unlike the preceding australopithecus species, Habilis had completely evolved for a bipedal lifestyle. They also had larger brainsat over 600 cubic centimeters.

Habilis were shaped differently, too. Their skulls was smoother and rounder compared to australopithecus, their faces projected less, and theur teeth were smaller and narrower. Still, habilis were small compared to modern humans, averaging about 75 pounds. Their diet, as told by the Smithsonian, included hard to chew foods like woody plants. Habilis also ate meat, which is known because of tool and bone evidence. In fact, this species’ name, Homo habilis, literally means “handy man.” At the time of their discovery in 1964, it was thought that they were the earliest users of tools. However, it has been shown that australopithecus species may have been using tools earlier.

Homo habilis is often put forward as the ancestor of all other human species.