Leakey, Mary Douglas Nicol (1913 – 1996) English Paleontologist and Anthropologist

views updated

Mary Douglas Nicol Leakey (1913 – 1996)
English paleontologist and anthropologist

For many years Mary Leakey lived in the shadow of her husband, Louis Leakey, whose reputation, coupled with the prejudices of the time, led him to be credited with some of his wife's discoveries in the field of early human archaeology. Yet she has established a substantial reputation in her own right and has come to be recognized as one of the most important paleoanthropologists of the twentieth century. It was Mary Leakey who was responsible for some of the most important discoveries made by Louis Leakey's team. Although her close association with Louis Leakey's work on Paleolithic sites at Olduvai Gorge—a 350-mi (564-km) ravine in Tanzania—has led to her being considered a specialist in that particular area and period, she has in fact worked on excavations dating from as early as the Miocene Age (an era dating to approximately 18 million years ago) to those as recent as the Iron Age of a few thousand years ago.

Mary Leakey was born Mary Douglas Nicol on February 6, 1913, in London. Her mother was Cecilia Frere, the great-granddaughter of John Frere, who had discovered prehistoric stone tools at Hoxne, Suffolk, England, in 1797. Her father was Erskine Nicol, a painter who himself was the son of an artist, and who had a deep interest in Egyptian archaeology. When Mary was a child, her family made frequent trips to southwestern France, where her father took her to see the Upper Paleolithic cave paintings. She and her father became friends with Elie Peyrony, the curator of the local museum, and there she was exposed to the vast collection of flint tools dating from that period of human prehistory. She was also allowed to accompany Peyrony on his excavations, though the archaeological work was not conducted in what would now be considered a scientific way—artifacts were removed from the site without careful study of the place in the earth where each had been found, obscuring valuable data that could be used in dating the artifact and analyzing its context. On a later trip, in 1925, she was taken to Paleolithic caves by the Abbe Lemozi of France, parish priest of Cabrerets, who had written papers on cave art. After her father's death in 1926, Mary Nicol was taken to Stonehenge and Avebury in England, where she began to learn about the archaeological activity in that country and, after meeting the archaeologist Dorothy Liddell, to realize the possibility of archaeology as a career for a woman.

By 1930 Mary Nicol had undertaken coursework in geology and archaeology at the University of London and had participated in a few excavations in order to obtain field experience. One of her lecturers, R. E. M. Wheeler, offered her the opportunity to join his party excavating St. Albans, England, the ancient Roman site of Verulamium; although she only remained at that site for a few days, finding the work there poorly organized, she began her career in earnest shortly thereafter, excavating Neolithic (early Stone Age) sites in Henbury, Devon, where she worked between 1930 and 1934. Her main area of expertise was stone tools, and she was exceptionally skilled at making drawings of them. During the 1930s Mary met Louis Leakey, who was to become her husband. Leakey was by this time well known because of his finds of early human remains in East Africa; it was at Mary and Louis's first meeting that he asked her to help him with the illustrations for his 1934 book, Adam's Ancestors: An Up-to-Date Outline of What Is Known about the Origin of Man.

In 1934 Mary Nicol and Louis Leakey worked at an excavation in Clacton, England, where the skull of a hominid—a family of erect primate mammals that use only two feet for locomotion—had recently been found and where Louis was investigating Paleolithic geology as well as fauna and human remains. The excavation led to Mary Leakey's first publication, a 1937 report in the Proceedings of the Prehistoric Society.

By this time, Louis Leakey had decided that Mary should join him on his next expedition to Olduvai Gorge in Tanganyika (now Tanzania), which he believed to be the most promising site for discovering early Paleolithic human remains. On the journey to Olduvai, Mary stopped briefly in South Africa, where she spent a few weeks with an archaeological team and learned more about the scientific approach to excavation, studying each find in situ —paying close attention to the details of the geological and faunal material surrounding each artifact. This knowledge was to assist her in her later work at Olduvai and elsewhere.

At Olduvai, among her earliest discoveries were fragments of a human skull; these were some of the first such remains found at the site, and it would be twenty years before any others would be found there. Mary Nicol and Louis Leakey returned to England. Leakey's divorce from his first wife was made final in the mid-1930s, and he and Mary Nicol were then married; the couple returned to Kenya in January of 1937. Over the next few years, the Leakeys excavated Neolithic and Iron Age sites at Hyrax Hill, Njoro River Cave, and the Naivasha Railway Rock Shelter, which yielded a large number of human remains and artifacts.

During World War II, the Leakeys began to excavate at Olorgasailie, southwest of Nairobi, but because of the complicated geology of that site, the dating of material found there was difficult. It did prove to be a rich source of material, however; in 1942 Mary Leakey uncovered hundreds, possibly thousands, of hand axes there. Her first major discovery in the field of prehuman fossils was that of most of the skull of a Proconsul africanus on Rusinga Island, in Lake Victoria, Kenya, in 1948. Proconsul was believed by some paleontologists to be a common ancestor of apes and humans, an animal whose descendants developed into two branches on the evolutionary tree: the Pongidae (great apes) and the Hominidae (who eventually evolved into true humans). Proconsul lived during the Miocene Age, approximately 18 million years ago. This was the first time a fossil ape skull had ever been found—only a small number have been found since—and the Leakeys hoped that this would be the ancestral hominid that paleontologists had sought for decades. The absence of a "simian shelf," a reinforcement of the jaw found in modern apes, is one of the features of Proconsul that led the Leakeys to infer that this was a direct ancestor of modern humans. Proconsul is now generally believed to be a species of Dryopithecus, closer to apes than to humans.

Many of the finds at Olduvai were primitive stone hand axes, evidence of human habitation; it was not known, however, who had made them. Mary's concentration had been on the discovery of such tools, while Louis's goal had been to learn who had made them, in the hope that the date for the appearance of toolmaking hominids could be moved back to an earlier point. In 1959 Mary unearthed part of the jaw of an early hominid she designated Zinjanthropus (meaning "East African Man") and whom she referred to as "Dear Boy"; the early hominid is now considered to be a species of Australopithecus —apparently related to the two kinds of australopithecine found in South Africa, Australopithecus africanus and Australopithecus robustus —and given the species designation boisei in honor of Louis Leakey's sponsor Charles Boise. By means of potassium-argon dating, recently developed, it was determined that the fragment was 1.75 million years old, and this realization pushed back the date for the appearance of hominids in Africa. Despite the importance of this find, however, Louis Leakey was slightly disappointed, as he had hoped that the excavations would unearth not another australopithecine, but an example of Homo living at that early date. He was seeking evidence for his theory that more than one hominid form lived at Olduvai at the same time; these forms were the australopithecines, who eventually died out, and some early form of Homo, which survived—owing to toolmaking ability and larger cranial capacity—to evolve into Homo erectus and, eventually, the modern human. Leakey hoped that Mary Leakey's find would prove that Homo existed at that early level of Olduvai. The discovery he awaited did not come until the early 1960s, with the identification of a skull found by their son Jonathan Leakey that Louis designated as Homohabilis ("man with ability"). He believed this to be the true early human responsible for making the tools found at the site.

In her autobiography, Disclosing the Past, released in 1984, Mary Leakey reveals that her professional and personal relationship with Louis Leakey had begun to deteriorate by 1968. As she increasingly began to lead the Olduvai research on her own, and as she developed a reputation in her own right through her numerous publications of research results, she believes that her husband began to feel threatened. Louis Leakey had been spending a vast amount of his time in fundraising and administrative matters, while Mary was able to concentrate on field work. As Louis began to seek recognition in new areas, most notably in excavations seeking evidence of early humans in California, Mary stepped up her work at Olduvai, and the breach between them widened. She became critical of his interpretations of his California finds, viewing them as evidence of a decline in his scientific rigor. During these years at Olduvai, Mary made numerous new discoveries, including the first Homo erectus pelvis to be found. Mary Leakey continued her work after Louis Leakey's death in 1972. From 1975 she concentrated on Laetoli, Tanzania, which was a site earlier than the oldest beds at Olduvai. She knew that the lava above the Laetoli beds was dated to 2.4 million years ago, and the beds themselves were therefore even older; in contrast, the oldest beds at Olduvai were two million years old. Potassium-argon dating has since shown the upper beds at Laetoli to be approximately 3.5 million years old. In 1978 members of her team found two trails of hominid footprints in volcanic ash dated to approximately 3.5 million years ago; the form of the footprints gave evidence that these hominids walked upright, thus moving the date for the development of an upright posture back significantly earlier than previously believed. Mary Leakey considers these footprints to be among the most significant finds with which she has been associated.

In the late 1960s Mary Leakey received an honorary doctorate from the University of the Witwatersrand in South Africa, an honor she accepted only after university officials had spoken out against apartheid. Among her other honorary degrees are a D.S.Sc. from Yale University and a D.Sc. from the University of Chicago. She received an honorary D.Litt. from Oxford University in 1981. She has also received the Gold Medal of the Society of Women Geographers.

Louis Leakey was sometimes faulted for being too quick to interpret the finds of his team and for his propensity for developing sensationalistic, publicity-attracting theories. In recent years Mary Leakey had been critical of the conclusions reached by her husband—as well as by some others—but she did not add her own interpretations to the mix. Instead, she has always been more concerned with the act of discovery itself; she wrote that it is more important for her to continue the task of uncovering early human remains to provide the pieces of the puzzle than it is to speculate and develop her own interpretations. Her legacy lies in the vast amount of material she and her team have unearthed; she leaves it to future scholars to deduce its meaning.

[Michael Sims ]