Aotus

Night monkeys, also known as owl monkeys or douroucoulis (/duːruːˈkuːliz/), are nocturnal New World monkeys of the genus Aotus, the only living member of the family Aotidae (/eɪˈɒtɪdiː/). The genus comprises eleven species which are found across Panama and much of South America in primary and secondary forests, tropical rainforests and cloud forests up to 2,400 metres (7,900 ft). Night monkeys have large eyes which improve their vision at night, while their ears are mostly hidden, giving them their name Aotus, meaning "earless".

Night monkeys are the only truly nocturnal monkeys, although some cathemeral populations of Azara's night monkey have irregular bursts of activity during day and night. They have a varied repertoire of vocalisations and live in small family groups of a mated pair and their immature offspring. Night monkeys have monochromatic vision which improves their ability to detect visual cues at night.