Hadar in brief
Hadar is a stretch of badlands in the Afar Depression of northeastern Ethiopia, along the Awash River, where the African continent is slowly being pulled apart. Sediments laid down by ancient rivers and lakes, called the Hadar Formation, have been tilted and eroded into gullies, and they hold fossils from about 3.4 to 2.9 million years ago. Those layers are interleaved with volcanic ash, which can be dated, and the dates are among the best for any early human site.
The area is best known for one species, Australopithecus afarensis, and for one individual, Lucy.
How the work began
In 1972 the French geologist Maurice Taieb surveyed the area and found fossils. In 1973 a French and American group, the International Afar Research Expedition, began work there, with Taieb, the American anthropologist Donald Johanson and the French paleontologist Yves Coppens as its leaders. In 1973 Johanson found the knee joint of a small creature, catalogued AL 129, which showed by its angle that its owner had walked upright, about three million years ago. It was a surprise, since few expected an upright walker that old.
Lucy and the First Family
On 24 November 1974 Johanson and Tom Gray, a student, found part of an arm bone and then much of a single skeleton at locality AL 288. That evening the team played the Beatles song “Lucy in the Sky with Diamonds” in camp, and the skeleton became Lucy. In Ethiopia she is called Dinkinesh, “you are marvellous”. The bones are about 3.2 million years old.
In 1975 the team found, at a nearby locality, AL 333, a huge group of fossils: more than 200 pieces from at least 13 (and perhaps as many as 17) individuals of both sexes and all ages. It was called the First Family, and for a time it was seen as evidence of a group that died together, for example in a flood. Later researchers have questioned that, and it may simply be an accumulation of remains.
Fieldwork at Hadar stopped in 1977, when political upheaval and war reached Ethiopia. It restarted in 1990 under Johanson and has continued since, with the Institute of Human Origins at Arizona State University.
Key finds
- AL 129. The 1973 knee joint, the first sign of upright walking at Hadar.
- Lucy (AL 288-1). About 40 percent of one adult skeleton.
- The First Family (AL 333). More than 200 pieces from at least 13, and possibly as many as 17, individuals.
- AL 444-2. The most complete adult skull of A. afarensis, found in 1992 and published in 1994. It is large, probably a male.
- Ledi-Geraru. A site north of Hadar. In 2013 a lower jaw about 2.8 million years old was found there, and described in 2015 as the oldest known fossil of the genus Homo, around 400,000 years older than anything else attributed to it at that time.
Why Hadar matters
Hadar showed that upright walking started long before large brains, and gave scientists a large sample of a single early species, with children and adults, males and females, so that the range of variation could be studied. That range, with males much larger than females, is the basis for much of what is said about afarensis today. Its dated layers, and the fossil animals and plants in them, show what the environment was like: a mixture of woodland, bush and grassland beside rivers and lakes.
Visiting
Hadar is remote, hot and in a region where conditions vary, and it is normally visited only by research teams. Check official travel advice before planning any trip to the Afar region. Lucy herself is kept in the National Museum of Ethiopia in Addis Ababa, where a cast is displayed, See also the Lucy species page.
Sources
- Johanson, D. C. and Edey, M. (1981). Lucy: The Beginnings of Humankind. Simon and Schuster.
- Kimbel, W. H. and Delezene, L. K. (2009). “Lucy” redux: a review of research on Australopithecus afarensis. Yearbook of Physical Anthropology 52: 2 to 48.
- Villmoare, B. and others (2015). Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia. Science 347: 1352 to 1355.
- Smithsonian National Museum of Natural History, Human Origins Program. Australopithecus afarensis.