Aotus nigriceps, commonly known as the black-capped night monkey, is a species of owl monkey found in the tropical forests of South America. They are characterized by their large eyes, which are adapted for nocturnal vision, and their distinctive black cap of fur on their heads. These monkeys are primarily arboreal, spending most of their time in trees, and are known for their social behavior, often living in small family groups. This species is unique among primates due to its nocturnal lifestyle, being one of the few truly night-active monkeys. Aotus nigriceps primarily feeds on fruits, insects, and small vertebrates. Their conservation status is of concern due to habitat loss and hunting, making efforts to protect their natural environment essential for their survival.