A new study of the teeth of 19 australopithecines from two famous cave sites in South Africa suggests that, when it came time for members of the human family to find a mate in South Africa about 2 million years ago, females moved away from their birthplaces far more often than males.
     Lead author Sandi Copeland, a paleo-anthropologist at the University of Colorado at Boulder (USA), along with colleagues, analysed tooth enamel from two species closely related to our direct australopithecine ancestor. The pattern held for both species.
     Copeland says, "This is the first direct evidence that exists for dispersal patterns among early hominins." The findings suggest that such patrilocal organisation of social groups is ancient in human ancestors, perhaps dating back to the common ancestor we shared with chimpanzees, as some researchers have proposed. This is similar to the dispersal pattern found in chimpanzees, bonobos, and many human groups, but dissimilar to that of most gorillas and other primates.
     Copeland isn't sure why males would move less than females in a region where there were no natural barriers. She plans to see if the pattern holds in australopithecines in other parts of Africa - to see if this was the usual way australopithecines organised their clans.
     It is still not clear where the roaming female australopithecines identified in the study spent their formative years, she added.

Edited from Popular Archaeology, EurekAlert!, Science (1 June 2011), Past Horizons (2 June 2011)