Ardi’s Ischium

If we make all three pelvises the same size, you can see Ardi’s ischium is long and pronounced like the chimpanzee’s. It may have supported muscles for active climbing.

A chimpanzee pelvis with a bracket alongside it marking the height of the ischium.
Chimpanzee ischium
An Ardipithecus pelvis with a bracket alongside it marking the height of the ischium.
Ardipithecus ischium
A human pelvis with a bracket alongside it marking the height of the ischium.
Human ischium