The pro-"gawd molded us out of dirt" crowd will hate this:
WASHINGTON (Reuters) - The way orangutans navigate fragile tree branches in search of fruit has led scientists to propose that human ancestors with similar lifestyles may have begun walking on two legs earlier than previously thought.
Three British scientists, writing on Thursday in the journal Science, suggested that bipedal walking arose in arboreal apes 17 to 24 million years ago, rather than between 4 and 8 million years ago as a leading hypothesis indicates.
The study by Susannah Thorpe and Roger Holder of the University of Birmingham and Robin Crompton of the University of Liverpool focused on a vital question in human evolution -- how human ancestors came to walk on two legs rather than four.
Upright walking on two legs is seen as a defining human characteristic.
http://news.yahoo.com/s/nm/20070531/sc_nm/orangutans_walking_dc