lived: 4.2 to 1.2 million years ago
brain size: 310 - 530 cubic centimeters
intelligence: used simple tools (such as sticks), probably had some form of language
largest group size: 55
other: Australopithecus only differed from Ardipithecus and earlier ancestors in that it walked upright, or was bipedal, and may have had a slightly larger brain.