AUTHOR COMMENTARIES

Please tell us a little about your research and educational background.

I am interested in revealing as much as possible about the patterns and processes of human evolution. I went to high school in southern California, and took B.S. degrees in Anthropology and Biology in the 1960s at the University of California, Riverside. I did a Ph.D. in Biological Anthropology at the University of Michigan, and returned to California where I have been on the faculty at Berkeley since the 1970s. Much of my education, however, has come at museums and field sites around the world.

What do you consider the main focus of your research, and what drew your interest to this particular area?

The main foci are temporal (the last six million years) and spatial (Africa). I co-direct a long-term investigation of the Middle Awash paleoanthropological study area in the Horn of Africa, deep the Afar rift of Ethiopia, where we have been researching a thick (>1 km) succession of ancient sediments containing the biological and technological remains of human ancestors.

One of your most-cited papers in our database is the 1999 Science article, "Australopithecus garhi: A new species of early hominid from Ethiopia." Would you walk our readers through this discovery and its significance?

About halfway through the sedimentary stack in the study area, there is a volcanic ash horizon dated to 2.5 million years ago. This is about the time that the first stone tools appear in the world archaeological record. But their makers have been elusive—not many hominid fossils of this age have been found, and none had been found from this part of Africa.

Just above the dated horizon we found the remains of several hominid individuals, along with some cutmarked and fractured animal bones. These represent the earliest evidence of large mammal butchery in the human evolutionary record and they were published as a companion to the paper on the associated hominid fossils.

We described the fossils as a new species, which is possibly the toolmaker and tool user. The name "garhi" is from the language of the local Afar people, and it means "surprise" because we were surprised to find a hominid of this age with such large front and back teeth, with such a primitive face and braincase.

What would you say has been your most significant finding to date?

I've been fortunate to have been involved with many discoveries. The most evocative was the excavation of the earliest hominid footprints in Tanzania during the 1970s. The most significant has been the compilation of this unique six-million-year record of human evolution in a single valley in Africa. Right now we are working on a partial skeleton recovered from 4.4 million years ago, which is throwing new light on the earlier part of our family tree.

Where do you see this research going in five to ten years?

More teams are working in more places, so the pace of discovery over the last decade has been boosted. However, these paleobiological and archaeological resources are fragile and limited, and they are only found in a few places on earth.

It is difficult to predict what will happen next, but the integration of new digital technologies into the pursuit of the ancient past is also playing a role in accelerating the pace at which our knowledge is expanding.

This is happening both in the laboratory and in the field, but it is from the field sites that the major new finds will be made by indigenous African scholars now making their marks in this international discipline.

What should the "take-away lesson" about your work be for the general public?

Our ancestors and close (but extinct) relatives are already well represented in the fossil record. Combined with independent evidence from the genetic realm, it is already clear that humans got here by evolution. And Darwin was right: all humans trace their evolutionary roots to Africa.

Tim D. White, Ph.D.
Professor
Department of Integrative Biology
University of California, Berkeley
Berkeley, CA, USA