In 1933, the young superstar Louis Leakey announced the find of Homo kanamensis, an ancient human species, based on a mandible he found in Kanam fossil beds in Africa. It was the first ancestral human Leakey named, and geologists and paleontologists congratulated him on his excellent work. Yet when P.G.H. Boswell visited Leakey's dig site afterwards, he was not impressed. The stakes Leakey had driven into the ground to mark the fossil locations were gone. (Leakey had assumed that iron stakes would be more durable than wooden ones. He was right. Iron stakes were also more valuable to whoever pulled them out of the ground and carried them away.) He had photographed the site but later learned that his camera wasn't working. Leakey couldn't be exactly certain just where he found the fossil, hence he couldn't get an exact date from the fossil beds. Boswell didn't keep quiet about the incident, and Louis Leakey's career was nearly squashed before it began.
Louis Leakey had grown up in Africa, the son of missionary parents. His education came partly from spinster governesses and partly from Kenyan tribal elders, an unusual combination. A later stint in a boarding school in England disagreed with him; he didn't fit in, and he hated the endless rules. While still a boy, he had decided that archaeology was his passion and that humans arose in Africa. He vowed to unearth African prehistory and to find the world's earliest human.
After the Kanam controversy halted Louis Leakey's meteoric rise to fame, his reputation almost didn't recover. But as the years passed, he and his family made other finds, including Paranthropus boisei, originally named Zinjanthropus boisei, and he became perhaps the world's most famous paleoanthropologist. While much of the paleoanthropology community clung to a ladderlike model of human evolution, insisting there could only have been a one human species at a time, Louis Leakey argued that multiple hominid species coexisted in Africa, an idea now demonstrated to be correct.
Unfortunately, the awkwardness incited by the Kanam controversy wasn't unique. Leakey was often quick to name new species without much supporting fossil evidence, and controversy followed many of his interpretations. Particularly troublesome to the scientific community was Homo habilis, which stretched the genus Homo to include a cranial capacity of an unprecedented small size, and based the species identification largely on presumed behavioral characteristics that no one could prove. In 2014, the 50th anniversary of the naming of this species, paleoanthropologist Bernard Wood opined in Nature:
I have been involved with H. habilis for all but two of its 50 years, starting in 1966, when I analysed the ankle bone . . . Far from being like that of modern humans, the bone is a much better match for an australopith. Other features of H. habilis have also turned out to be less like those of modern humans than Louis and his team suggested. . . . What little evidence there is about its body shape, hands and feet suggest that H. habilis would be a much better climber than undisputed human ancestors. So, if H. habilis is added to Homo, the genus has an incoherent mishmash of features. Others disagree, but I think you have to cherry-pick the data to come to any other conclusion. My sense is that handy man should belong to its own genus, neither australopith nor human.
In the same piece, Wood also disputed recent research suggesting that Homo erectus, Homo habilis and Homo rudolfensis be reclassified as a single species, so he might be called something of a species splitter, but he was hardly alone in his concerns about Homo habilis. Paleoanthropologist Ian Tattersall has also noted "the huge extension of the genus Homo, in both time and morphology." Tattersall also discussed the Leakeys' assertion that Handy Man had constructed a windbreak at Olduvai from loosely piled stones.
Handy Man had possessed a home! Later work suggested that the ring actually consisted of stones shattered and moved by the expanding roots of a tree, but at the time the additional cultural complexity implied by the windbreak was seen to support the notion that early Homo had roamed the East African savannas a very long time ago.
Another low point for Louis Leakey came with his assertion that that he'd found a human ancestor over 19 million years old. The fossil Leakey based this on, Kenyapithecopus was later identified as a fossil ape. Leakey's career probably reached its lowest point, however, at the Calico dig site in the Mojave Desert; he believed evidence from the site could prove human habitation in the New World as much as 100,000 years ago. Although the earliest possible date for human habitation in the New World has certainly been pushed back, it doesn't approach his number, and he had no reliable evidence. Even his own wife thought he'd lost his edge.
Part of Louis Leakey's trouble was his inability to sustain a long-term devotion to any one thing (including marriage). He deserted his first wife for Mary Nicol (later Mary Leakey), and womanized throughout his second marriage, which likely contributed more to his separation from Mary Leakey than the Calico fiasco. For decades, he spread himself too thin between too many fossil digs, museum posts, fundraisers and lectures. Through it all, he suffered multiple heart attacks, injuries, and even blood clots in his brain. Encouragement to slow down from his family and physicians fell on deaf ears. But Louis Leakey's wide assortment of interests had a positive side: He encouraged a variety of research projects throughout his life, including Jane Goodall's chimpanzee studies and Dian Fossey's mountain gorilla studies — which may very well have saved that species from extinction. Though he sometimes worked as a government spy and helped prosecute suspected Kenyan revolutionaries, he pushed for desegregation, and opened museum doors to native Africans, much to the annoyance of European expatriates.
And Louis Leakey adopted techniques that enabled paleoanthropologists to finally attach absolute dates to hominid fossils. By working with geologists and physicists, he worked out the dates of Pleistocene deposits and the fossils found in them. The fossil-rich rock layers at Olduvai Gorge occurred between layers of volcanic rocks that could be dated through radiometric methods. The dates attached to Olduvai rock layers could then be compared to dates derived from paleomagnetic sequences, such as from the mid-Atlantic Rift. In the early 1950s, he argued that Olduvai rock layers might be as young as 15,000 years; years later, he understood that the volcanic rocks under Zinjanthropus boisei were roughly 1.75 million years old.
Perhaps Louis Leakey's greatest gift was his charisma. The 1959 discovery of "Zinj" meant close connections with the National Geographic Society, and another society paid for his participation in the University of Chicago's Darwin Centennial celebration. Leakey wisely made the best of his first trip to the United States, delivering 66 lectures at 17 different universities in a single month. Audiences packed auditoriums to hear him speak. He used the lecture fees and donations to fund more fieldwork, and kept looking for more protégés. Were it not for Louis Leakey, many of the best minds in paleoanthropology might never have been inspired, and many of the best finds might never have been made.
Narrative text and graphic design © by Michon Scott - Updated April 29, 2017