Aotus

Aotus is a genus of nocturnal New World monkeys, commonly called night monkeys, owl monkeys or douroucoulis, and is the only living genus in the family Aotidae. It comprises eleven species distributed across Panama and much of South America, inhabiting primary and secondary forest, tropical rainforest and cloud forest up to 2,400 meters elevation. Its large eyes support nocturnal vision, its genus name meaning earless reflects ears largely hidden beneath fur, and it is considered the only genus of truly nocturnal monkeys, though some populations of Azara's night monkey show cathemeral, both day and night, activity.