"I don't see a difference

"I don't see a difference between a chimpanzee," he states unequivocally, "and my 4 1/2-year-old son." (...)

Some talking points: Chimps have complex social interactions. They use tools. Research by Harvard anthropologist Richard Wrangham, among others, has shown that, even in the wild, they demonstrate an idea of the future and remember the past. They can count. And they can communicate in sign language at the level of a 3- or 4-year-old child.