Mary Leakey

Mary Leakey (February 6 1913 – December 9 1996) was a British physical anthropologist, who, along with others, discovered the first skull of a fossil ape on Rusinga Island. For much of her career she worked with her husband Louis Leakey in the Olduvai Gorge, uncovering the tools and fossils of ancient hominines. She also discovered the Laetoli footprints.

History

Mary Leakey was born Mary Nicol on February 6, 1913 in London, England. Since her father worked as a painter, the Nicol family would move from place to place, visiting such locations as France and Italy. After a time, the family moved to Dordogne in France. In nearby Cabrerets, Abbe Lemozi was leading an excavation. It was here that her interest in prehistory was sparked. Mary's father died in 1926 and her mother placed her in a Catholic convent from which she was repeatedly expelled. After leaving the convent, she attended lectures for archaeology and geology at the University of London. She entered the field as an illustrator for Dr. Gertrude Caton-Thompson's book, The Desert Fayoum, and through Dr. Caton-Thompson, met Louis Leakey. She showed him her illustrations and he arranged for her to illustrate his book, Adam's Ancestors. They were married in 1936 and had three sons: Jonathan in 1940, Richard in 1944, and Philip in 1948. Louis died on October 1, 1972 of a heart attack. Mary died on December 9, 1996 at the age of 83.

Excavations

Her first important excavation was at Hembury Fort in Devon, England in May of 1934. Later that year, Mary performed her own excavation at Jaywick Sands. She also published her first scientific paper. The years 1935 to 1959, spent at Olduvai Gorge in the Serengeti plains of Northern Tanzania, yielded many stone tools from primitive stone-chopping instruments to multi-purpose hand axes. These finds came from Stone Age cultures dated as far back as 100,000 to two million years ago. The Leakeys unearthed a Proconsul africanus skull, dated to be twenty million years old, on Rusinga Island, in October of 1947. This skull was the first skull of a fossil ape ever to be found and to this day only three of these apes are known. Their next discovery, in 1959, was a 1.75 million-year-old Australopithecus boisei skull. They also found a less robust Homo habilis skull and bones of a hand. After reconstructing the hand, it was proven the hand was capable of precise manipulation. Many more remains were found at this site. In 1965 the husband and wife team uncovered a Homo erectus skull, dated at one million years old.

After Mary's husband passed on, she continued her work at Olduvai and Laetoli. It was here at the Laetoli site, that she discovered Homo fossils that were more than 3.75 million-years-old. She also discovered fifteen new species and one new genus. From 1976 to 1981 Mary and her staff worked to uncover the Laetoli hominid footprint trail which was left in volcanic ashes some 3.6 million years ago. The years that followed this discovery were filled with research at Olduvai and Laetoli, the follow-up work to discoveries and preparing publications.

Laetoli

The Lower Paleolithic site of Laetoli in Tanzania is famous for its human footprints, preserved in volcanic ash (Site G). The site is located 45 km south of Olduvai.

Laetoli Site, February 2006

The site is Pliocene, dated by the K/Ar method to 3.7 million years ago.

The footprints

A line of hominid footprints, discovered in 1976-77 by Mary Leakey, Richard Hay and their team, is preserved in powdery ash from an eruption of the 20 km distant Sadiman Volcano. Soft rain cemented the ash-layer (15 cm thick) to tufa without destroying the prints. In time, they were covered by other ash deposits. The hominid prints were produced by three individuals, one walking in the footprints of the other, making the original tracks difficult to discover. As the tracks lead in the same direction, they might have been produced by a group- but there is nothing else to support the common reconstruction of a nuclear family visiting the waterhole together.

	hominid 1	hominid 2
length of footprint	21.5 cm	18.5 cm
width of footprint	10 cm	8.8 cm
length of pace	47.2 cm	28.7 cm
reconstructed body-size	1.34-1.56 m	1.15-1.34 m

The footprints demonstrate that the hominids walked upright habitually, as there are no knuckle-impressions. The feet do not have the mobile big toe of apes; instead, they have an arch (the bending of the sole of the foot) typical of modern humans. They seem to have moved in a leisurely stroll.

Other animals

Other prints show the presence of twenty other animal species, among them hyenas, wild cats (Machairodont), baboons, wild boar, giraffes, gazelles, rhinos, several kinds of antelope, hipparion, buffalo, elephants (of the extinct Deinotherium genus), hare and birds. Traces of raindrops can be seen as well. Few prints are superimposed, which indicates that they were rapidly covered up again. Most of these animals are represented by skeletal remains as well.

Human remains

The remains of 13 hominids have been found, mainly mandibles and teeth. They show affinities to the female skeleton Lucy from Hadar, Ethiopia. Most scholars classify them as Australopithecus afarensis, but some stress the greater similarity to Homo and prefer to speak of Homo sp. indet.

A rather complete skull found at Ngaloba in 1976 has been dated to ca. 120 000-100 000 years B.C.E. It is very modern anatomically, with a cranial capacity of ca. 1.200 cm³, but the forehead is still very low.

Artifacts

No artifacts have been found in the vicinity. It is probable that stone was not yet used for tool production.

Awards

Mary and Louis were jointly awarded the Stopes Medal from the Geological Association in 1955. In March of 1962, the Leakey family took a trip to the United States to receive the Gold Hubbard Medal, the highest honor the National Geographic Society offers. In 1969, she earned her first Honorary Degree from the University of the Witwatersrand in Johannesburg.

Further reading

• Mary D. Leakey and J. M. Harris (eds), Laetoli: a Pliocene site in Northern Tanzania (Oxford, Clarendon Press 1987). ISBN 0198544413.
• Richard L. Hay and Mary D. Leakey, "Fossil footprints of Laetoli." Scientific American, February 1982, 50-57.

References

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External links

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