Charles Darwin, in his 1871 book Descent of Man, had suggested that because our closest evolutionary relatives, chimpanzees and gorillas, live in Africa, the earliest humans probably once lived there too. Leakey was just 13 when he decided to devote himself to the study of prehistory and find out if Darwin was right. As a young man, he thus challenged the conventional wisdom, which appealed to his contrarian nature. “I became excited with the idea that everyone was looking in the wrong place,” he later explained. In the fall of 1931, on his third expedition to East Africa but his first to Olduvai, he found primitive stone axes in ancient sediments, evidence that ancestors of humans had indeed lived in Africa. It was a significant discovery—“I was nearly mad with delight,” he recalled—but Leakey’s penchant for over-reaching soon got the better of him.
In addition to staking his career on the notion that Africa was the cradle of humankind, he also believed, given the fossil evidence, that the earliest bipedal human ancestors, or hominids, must have existed hundreds of thousands of years earlier than most other scientists were willing to say. Indeed, the reason for that first trip to Olduvai Gorge was to test the idea that a modern-looking skeleton, discovered by German scientist Hans Reck in 1913, was, as Reck claimed, about half a million years old—the age of the deposits in which it had been found.
Leakey, initially skeptical of Reck’s assertions, visited the site with Reck and soon agreed with him. They coauthored a letter to the British journal Nature reporting the new evidence for Reck’s original theory—which also appeared to confirm Leakey’s hunch that our first true ancestor lived farther back in prehistory. “[Reck] must be one of the few people who succeeded in swaying Louis once his mind was made up,” observes Leakey’s biographer Sonia Cole. But a few years later, other researchers, using improved geological methods, concluded that the skeleton wasn’t ancient at all, but had simply been buried in far-older sediments.
In 1932, Leakey was also making extravagant claims of antiquity for fossils from two sites in western Kenya, Kanam and Kanjera. The Kanam jawbone, Leakey boldly announced, was “not only the oldest human fragment from Africa, but the most ancient fragment of true Homo yet to be discovered anywhere in the world.” Ultimately, it was found that the Kanjera and Kanam specimens were relatively recent. Leakey’s reputation already had taken a beating when a British geologist visited Kanjera and reported that Leakey did not know exactly where he had found his famous fossil—an astonishing lapse for an anthropologist.
Leakey shrugged off his critics. He and Mary pressed on, and in 1948 they received their first real taste of public adulation with the discovery of a little skull of an 18-million-year-old ape called Proconsul. It was the first fossil ape skull ever found, and Mary flew with it to England so that Wilfrid Le Gros Clark, Leakey’s friend and an anthropologist at Oxford, could examine the specimen. The plane was met by reporters, photographers and newsreel cameramen. Later, with the skull on display at the airport, Mary told Leakey, “Two plainclothes detectives assigned to guard it never let it out of their sight.”