Owl monkeys are the world's only nocturnal monkey. They have large eyes for collecting as much of the dim light as possible. These monkeys clamber and leap between trees in their jungle homes in South America. They eat fruit, leaves, buds, shoots, insects, nectar, and small vertebrates.
Owl monkeys forage in small family groups of a monogamous mated pair and their offspring. The male provides all of the care for the young except for nursing. Families are territorial, territories are marked with scent secretions from the base of the tail.