Thermoregulation Theory was developed by Wheeler in 1984, suggesting that bipedal posture developed as hominids had to forage in the newly created savannahs, when the sun was overhead. Therefore, being bipedal would have meant that they would not have had to stop their foraging to look for shade as bipeds show 60% less body surface to the sun. Therefore, bipedalism would have meant that early humans had to deal with less thermal stress and the possibility of overheating was greatly reduced. Another advantage would be that there would have been less need for water. However, the problem is this theory only works when the sun is directly overhead. Also, bipedalism is proved to have evolved predominantly in the woodlands, not the savannah, and there is no evidence in the Australopithecine skeletons found that would prove this theory.