The Australopithecines averaged about four feet tall and stood upright. Males of this genus were of greater size than the female. This is parallel to the size ratio of apes. They also had primitive features that suggest they are evolutionary descendants of the earlier Homo habilis. The shared resemblance to ape features and Homo habilis help support the theory that ape and human evolution branched off of a single line 10-20 million years ago. Fossils also show that their diet consisted primarily of tough vegetation. There are also many similarities in bone structures between humans and Australopithecine. The femur and heel bones were made for walking upright and to support shock from walking and running. Also, the structure of the hip bones are wider than those in apes for the same reason. In the Australopithecine the hips are bigger, with a smaller birth canal than in humans. This is because they didn't need as much room to pass the infant's head because it was much smaller than human heads today. This difference in the hip structure actually helped the Australopithecine walk and run more efficiently than you and I do today.