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 ...

Howler monkeys are relatively small primates known for their incredibly loud, low-frequency roars that sound as if they come from a much larger creature. This is useful in the animal kingdom because ...

An extinct relative of the howler monkey may have been the first leaf-eating primate in South and Central America ...

A playful howler monkey seeks attention and affection, highlighting the gentle and social side of these lively primates.

A black howler monkey sits on a tree branch in the Amazon Rainforest, Brazil. The surrounding forest shows dense vegetation ...

Howler Monkeys Catching Flies in the Wild ...