Louis and Mary Leakey investigated an early human campsite at OLDUVAI Gorge, Tanzania, and found important hominid fossils more than 1.75 million years old. Their son Richard has found even earlier hominid fossils dating from as much as 3 million years ago. Leakey studied archaeology in college from 1922 to 1926. He then returned to Kenya where he investigated Stone Age cultures in East Africa.

From 1931 to1959, Louis and his second wife, Mary, worked at Olduvai Gorge reconstructing a long sequence of Stone Age cultures dating from approximately 2 million to 100,000 years ago. They documented the early history of stone technology from simple stone-chopping tools and flakes to relatively sophisticated, multipurpose hand axes. In 1959 the Leakeys discovered the skull of Australopithecus boisei (a species of the prehuman genus, AUSTRALOPITHECUS).

This skull was later dated at about 1.75 million years of age, using potassium-argon dating. Leakey claimed Homo HABILIS was the earliest toolmaker and a direct ancestor of modern humans. Many scientists disagreed, largely because the fossil fragments were small. By 1965 the Leakeys had found several other fossils at Olduvai, including a Homo ERECTUS cranium that is about 1 million years old.

Louis Leakey also experimented with techniques of making stone tools and attempted to understand how prehistoric hunter-gatherers obtained their food. He was a pioneer in primate research, encouraging such well-known social scientists as Jane GOODALL and Dian Fossey to study chimpanzees and gorillas. Leakey believed that such studies would increase understanding of early humans.

After Leakey’s death, Mary Leakey and their son Richard continued field research in East Africa. Mary Leakey did much of the fieldwork at Olduvai and has discovered Homo fossils more than 3.75 million years old at LAETOLI, located 40 km (25 mi) south of Olduvai. Richard Leakey has discovered more than 388 km² (1500mi²) of lower Pleistocene deposits on the eastern shore of Lake Turkana (Rudolf) in northern Kenya.

He found fragments of a more advanced hominid, known as SKULL 1470, which was dated by Leakey at 2.6 million years old. In 1984 he and his colleagues also found a nearly complete skeleton of a large Homo. erectus, dated as about 1.6 million years old. Kenya’s government appointed Leakey as Director of Wildlife Services in 1989 to help protect endangered elephants from ivory poachers. After months of turmoil, and a plane crash in which he lost both legs, he resigned in early 1994.