"But why is the Savannah hypothesis wrong? " It was announced on television. There was a surprising doco which stated flatly how the Savannah Hypothesis was now proven wrong. I'll do some searching on it when I get a chance. It was pretty technical as remember but seemed pretty clear cut. "You're aware, specifically, that various animals on the savannah benefit from vertical height, including antelopes and giraffes? Bipedalism reduces sun impact (though admittedly not so much for the head) and allows tool carrying." Bipedalism is a major change. Not an overnight adaptation. wading makes sense. Monkeys can be seen to walk like humans when wading. There is no example of Savannah animals becoming bipedal. Babboons are not bipedal. Gorilla's aren't bipedal. Not a single other primate or old world monkey or lemur or anything has attempted to become bipedal.