Today, all ape species (except for humans) live in forests, but four million years ago things were different. Africa was home to a range of apes that lived on open ground and walked upright as we do. The best known of these walking apes, Australopithecus, is probably our own ancestor.
■ When: 4–2 million years ago (Neogene)
■ Fossil location: Africa
■ Habitat: Open woodland, grassland
■ Height: 4–4. ft (1.2–1.4 m)
■ Diet: Fruit, seeds, roots, insects, small animals
In many ways, Australopithecus was like its very close relative the chimpanzee. It had a small, hair covered body, powerful arms for climbing, and a brain one-third the size of ours. However, its hip bones and feet were like those of modern humans, indicating that Australopithecus could walk upright, although less nimbly than we can. Some scientists think Australopithecus lived in social groups like those of gorillas, ruled by a single male that was much larger than the females.
Walking on only two feet left the arms free for other jobs, such as carrying. This was to be very important later in human evolution, when our ancestors made tools such as hunting weapons.
Scientists once thought our ancestors evolved large brains before they mastered the tricky business of walking. But Australopithecus proves the opposite was true—it could walk, but its brain was barely larger than a chimp’s. This animal didn’t have the brainpower needed for language and couldn’t talk, although individuals may have whooped and screeched to communicate.
Footprints from the past
In 1976, scientists found what looked like fossilized human footprints in Tanzania, Africa—but the prints turned out to be 3.6 million years old. They were left by a group of three Australopithecus walking over volcanic ash and clearly show that these animals could walk on two feet.
In 1975, scientists found fossilized remains of at least 13 Australopithecus bodies at the same site in Ethiopia. The find was nicknamed “the first family,” although they may have been unrelated victims of predators such as lions.
LANDSCAPE AND FOOD
Today, most apes live in jungles, but Australopithecus lived in a more open landscape—a mixture of grassy areas and patches of trees. Its large jaws and thickly enameled molars (back teeth) show it foraged for tough, plant foods like roots and seeds, but like other apes it probably had a very varied diet that included fruit, insects, and perhaps meat.
The chimpanzee is a very close relative of Australopithecus. Chimpanzees sometimes use rocks and sticks as simple tools. They use rocks to crack nuts and sticks to fish termites out of their nests. It’s likely that Australopithecus also used simple tools like these, but there’s little fossil evidence that it could make the kinds of stone tools that the later humans made.