Mary Douglas Nicol Leakey, archaeologist and paleoanthropologist, is credited with many anthropological discoveries including Homo habilis (1960), tool man who lived between 1.4 and 2.3 million years ago, and a 16 million year old fossil, Proconsul africanus (1948), an ancestor of both apes and humans.
She also uncovered 70 fossils in 1978, formed 3.66 million years ago, that provided “crucial evidence that walking on two legs was picked up early in the human lineage.”
Born 06 February 1913 in London as Mary Douglas Nicol, she traveled as a child to Italy, Switzerland and France with her parents; her father was a painter. In 1933, Mary illustrated The Desert Fayoum, written by archaeologist, Gertrude Caton-Thompson.
That work led to meeting Louis Seymour Bazett Leakey, who asked her to illustrate his upcoming book, Adam’s Ancestors. He was married and 10 years her senior. After his divorce, the two married in 1937 and immediately headed to Kenya.
In 1948, Mary found the fossil Proconsul africanus in Kenya; it was comprised of half the skull, the upper and lower jaws, and all the teeth. About 16 million years old, the fossil “provided anthropologists with their first cranium from what was thought to be the missing link–a tree-dwelling monkey boasting a bigger brain than its contemporaries.”
Mary and Louis worked throughout Kenya and Tanzania. Their first big break came in 1959, in the Olduvai Gorge, Tanzania. Mary found a hominid skull, soon dubbed Zinjanthropus (Zini), that was about about 2 million years old. The first such skull to be found in East Africa, Zinj became the first of a new group, Australopithecus boisei.
Speaking to Scientific American in 1994, Mary remarked that the fossil “caught the imagination of the National Geographic Society, and as a result they funded us for years. That was exciting.”
One of Leakey’s favorite finds is an assortment of Miocene fossils: intact fruits, seeds, insects–including one entire ant nest–and a lizard with its tongue hanging out. They lay all over the sandy ground of Rusinga Island. “We only found them because we sat down to smoke a cigarette, hot and tired, and just saw all these fruits lying on the ground next to us. Before that we had been walking all over them all over the place.” She stops. “You know, you only find what you are looking for, really, if the truth be known.”
According to Scientific American, Mary made her most dramatic discovery in 1978*, after Louis had died in 1972. In Laetoli, Tanzania, she uncovered the earliest footprints (3.66 million years old) that are “widely accepted as the oldest unequivocal evidence” of human bipedalism.
In her 1984 autobiography, Disclosing the Past, Mary also described the discovery of the Laetoli footprints as one of her most important.
In addition, “[h]er artifact tagging and recording systems are now considered standard practice within archaeology and paleoanthropology.”
Almost all hominin footprints that have been discovered have been attributed the genus Homo. These fossils have been attributed to the species Australopithecus afarensis, the same one as the famous Lucy from Ethiopia.
The footprints were preserved by ash fall from a volcanic eruption; the ground was wet when the hominins trod the area. Other footprints include elephants, giraffes and rhinoceroses.
The Laetoli site is still being investigated today. The Leakey Foundation continues her contributions to our “scientific knowledge, education, and public understanding of human origins, evolution, behavior and survival.” Check out their podcast.
*Some news reports say 1976.
Watch a short documentary at the NYTimes.