A. afar dimorphism

A. afar dimorphism

two femora bones

Two femora bones. On the left is a large, presumably male specimen and on the right is Lucy. The difference between these two gives the impression of a large size differences between the sexes. However, inclusion of the many intermediately sizes specimens from this species indicates that the size variation is similar to moderately dimorphic humans.

IMAGE: Phil Reno/Penn State