In their 2004 article in the journal Nature, Bramble and Lieberman write “Striding bipedalism is a key behavior of hominids that possibly originated soon after the divergence of the chimpanzee and human lineages .” Dr. Daniel Leiberman, a biology professor from Harvard also known as “The Barefoot Professor” suggests that a massive environmental change that took place on the African continent coinciding with the rise of running among humans.