Bipedalism is the basic adaption of the hominin line, and it is considered the main cause behind a suite of skeletal changes shared by all bipedal hominins. The earliest bipedal hominin is considered to be either "Sahelanthropus" or "Orrorin", with "Ardipithecus", a full bipedal, coming somewhat later. The knuckle walkers, the gorilla and chimpanzee, diverged around the same time, and either "Sahelanthropus" or "Orrorin" may be humans' last shared ancestor with those animals. The early bipedals eventually evolved into the australopithecines and later the genus "Homo". There are several theories of the adaptational value of bipedalism. It is possible that bipedalism was favored because it freed up the hands for reaching and carrying food, because it saved energy during locomotion, because it enabled long-distance running and hunting, or as a strategy for avoiding hyperthermia by reducing the surface exposed to direct sun.