ASU Research E-Magazine: The Urge to Dig

Ask Bill Kimbel about his work in the Afar region of Ethiopia, and he is quick to smile and respond with equal parts passion and commitment. You might as well mention the name of an old friend.

“I always look forward to returning the Ethiopia,” says Kimbel, a paleoanthropologist and director of science at Arizona State University’s Institute of Human Origins. “I enjoy looking for fossils, doing the research, and living in the magnificently beautiful Afar Desert with people I have known and worked with for many years.”

Kimbel divides his time between teaching at ASU and co-leading field projects at the site of Hadar, located in northern Ethiopia. It was at Hadar in November 1974 that a young scientist named Donald Johanson unearthed one of the most influential and significant fossil discoveries of the 20th century—the 3.2 million-year-old partial female skeleton known as Lucy. Her skull looked like that of an ape, yet she walked upright, like a human.

“Hadar has played a very important role in Ethiopian paleoanthropology,” Kimbel explains. “Everybody knows Lucy; she is an icon in paleoanthropology and has been since her discovery.”

The urge to dig came early for the ASU scientist. His interest in fieldwork predated the discovery of Lucy, and started just a few miles from his home in Pennsylvania. While a senior in high school, Kimbel worked as an archaeologist for the State of Pennsylvania, at Valley Forge State Park.

“My social studies professor introduced me to anthropology. The subject really captured my imagination,” Kimbel recalls.

In 1973, Kimbel took a course at Case Western Reserve University taught by Donald Johanson, then an assistant professor at the school in Cleveland, Ohio. That course solidified Kimbel’s interest in field research and, in particular, his interest in the Afar region of Ethiopia.

Kimbel made his first trip to Ethiopia during the winter of 1976. He signed on as a paleontological assistant with the International Afar Research Expedition. The group’s research was concentrated on site 333 at Hadar.

Lucy had been discovered two years earlier. Now the excavation team had uncovered the remains of more than 13 individuals from Australopithecus afarensis, the same species as Lucy.

Kimbel was 22 years old and had been seduced by the work. “It was a very exciting time. With every shovel full of dirt, I was digging myself a career,” he says.

He earned his degree in anthropology from Case Western Reserve in 1976. Then it was on to graduate school at Kent State University where he graduated in 1986 with a doctorate in biological sciences.

Between 1981 and 1985 Kimbel worked as curator at the Cleveland Museum of Natural History. At the same time, Johanson was setting up a human origins “think tank” in Berkeley, Calif. The new organization was fittingly called the Institute of Human Origins.

It didn’t take long before Kimbel moved to Berkeley to join Johanson at the Institute. In the early years, the IHO scientists collaborated on projects in the People’s Republic of China, Israel, Tunisia, and Tanzania, although Kimbel concentrated on his fieldwork at Hadar.

“My work at Hadar is focused on Australopithecus afarensis, and particularly the skull of Lucy’s species.” Kimbel says that even with the relative completeness of Lucy—over 70 percent of skeleton was recovered—the skull was very fragmentary.

That all changed in 1992 when colleague Yoel Rak discovered the first complete skull of afarensis. Rak found the skull at Hadar in deposits dated at about 3 million years old.

Kimbel says that his real satisfaction comes in the laboratory. All fossils found at the dig site are taken to a lab at Ethiopia’s National Museum in Addis Ababa. That is where researchers arrange the fossils on a table and begin the reconstruction process.

“The hardest work perhaps begins after the fossils have been found,” he says.

Scientists use dental picks, high-speed drills, and considerable patience. Kimbel and Rak spent many years cleaning and reassembling the skull. Fragment by fragment, they carefully fitted each piece into its proper place. In the end, the male skull was nearly 60 percent complete.

Scientists throughout the world consider the Hadar fossil discoveries to be an extremely rich source of information. They tell us much about Lucy’s species: how she walked, the shape of her teeth, the size of her brain, and what her skull looked like.

To date, scientists have unearthed more than 350 individual afarensis fossils. The fossils range in age from around 3.8 million to 3.0 million years. The Hadar site has supplied nearly 90 percent of those fossils.

“Our work at Hadar is very important; and it remains an extremely important site,” Kimbel adds.

Working with co-authors Rak and Johanson, Kimbel recently completed The Skull of Australopithecus afarensis.

Kimbel is passionate about his work. But he knows how to share that passion with other eager young minds. The opportunities to share and teach were enhanced when Johanson and the Institute of Human Origins moved from California to ASU in 1997.

“Our presence at ASU gives us the ability to do two things,” Kimbel explains. “First, we continue to carry out our research program both in the laboratory and overseas like we always have. But secondly, we get to interact with a terrific academic community of scholars, graduate students, and undergraduate students. In the previous history of IHO, that is something we’ve never been able to do in any formal way.”

Like Kimbel in 1976, new groups of graduate students are being provided the opportunity to conduct fieldwork in Ethiopia. The IHO scientists continue to do research as well as train the next generation of paleoanthropologists.

“Finding fossil hominids is an incomparable thrill. It is hard to describe the feeling of bending down and picking up a piece of jaw or the thigh bone from a creature that you recognize to have contributed genes to your own species,” Kimbel says.

“It was my professors who sparked my curiosity about anthropology. Now I have the opportunity to provide the same excitement for my students at ASU.”—Lenora Johanson