'Genetic time machine' reveals complex chimpanzee cultures

In recent decades, scientists have clearly demonstrated that chimpanzees, like humans, pass on complex cultures such as tool use from generation to generation. But human culture has become vastly more sophisticated, from the Stone Age to the Space Age, as new advances have been incorporated. Chimpanzee cultures haven't changed in the same way, which suggests that only humans have the remarkable ability to build more sophisticated cultures over time.