Possible Reason For Bipedalism

Early ancestors of humankind may have taken to bipedalism for any number of reasons, but a gorilla at the Philadelphia Zoo recently found a new one: cleaner food:

When Louis has his hands full of tomatoes or other snacks, he walks upright like a human to keep food and hands clean, rather than the typical gorilla stance of leaning forward on his knuckles.

This suggests a possible interesting path in evolution. Early ancestors of humanity may have chosen bipedalism for the ability to carry food and other objects, marking a transition to the tool-making era of our forebears.