Face of the past.

Scientists in Ethiopia have unearthed the 3.3-million-year-old skeleton of a young girl. The discovery is the oldest and most complete fossil of a child that has ever been found.

Studies of the fossilized teeth suggest that the girl was about 3 years old when she died. "It is very rare to find such an immature individual preserved so completely," says Tim White, co-director of the Human Evolution Research Center at the University of California at Berkeley. If the fragile bones of a child are left exposed, they are easily broken down by bacteria or damaged by animals. This skeleton was preserved because it was quickly buried in sediment during a flood. That covering protected the skeleton from decay.

The researchers have named the girl Selam, which means peace in some Ethiopian languages. Selam was an ancient hominid. This group includes modern humans and their ancestors, but not apes. Selam belonged to the species Australopithecus afarensis, which shares characteristics with both apes and modern humans. Examinations of her thigh, shin, and foot bones indicate that Selam walked upright on two legs. She also had long arms and long, curved fingers. These features suggest that Selam may have climbed trees and nested in the branches.