They had a brain size not much larger than modern apes, lacking the large brain of the genus "Homo". They were mainly bipedal, but probably capable of climbing and living at least partly in trees. Their arms were longer in proportion to their bodies, and this also suggests their inherited capacity to move above the ground. The efficiency of their walking is difficult to estimate, but they were not so well adapted to bipedalism as humans. The males were much larger than the females, which suggests a family arrangement with a dominant male and several females, as with modern apes. Nothing is known for certain about their use of tools.