Fark linked up this report detailing a new theory about the why's and how's of primate evolution. Instead of postulating food gathering or socialization as the primary engine, Lynne Isbell, an anthropologist at the University of California, Davis, believes it was all about the avoidance of what may have been the main tree-based predator when primates evolved... snakes. Each innovation by one group resulted in another innovation to counter it from the other, until we ended up with the sophisticated species we have today. It's an interesting theory, which provides many predictions, so we'll just have to see how it pans out.