Thirteen million years ago, a group of medium-sized monkeys known for guarding their territory among the treetops with fearsome "howls" started doing something new. These monkeys, among the oldest ...

Monkeys live throughout Asia, Africa, Central America, and South America. They’re distinct from other types of primate, like great apes (gorillas, chimpanzees, orangutans, bonobos, gibbons) and ...

• 13 million years ago, a medium-sized monkey known for guarding its territory among the treetops with a fearsome “howl” started doing something new. This monkey, one of the oldest known ancestors of ...