In the 1960s and 70s, a group of chimpanzees astonished the world by learning sign language. Only two remain and one question ...

Add Yahoo as a preferred source to see more of our stories on Google. When you buy through links on our articles, Future and its syndication partners may earn a commission. We know animals have their ...

At the turn of the 20th century, a famous horse named Clever Hans toured Germany. The horse stunned crowds as his trainer demonstrated the animal's alleged ability to understand German, tell time and ...