The black-headed night monkey is a small monkey of Amazonian forest, active mainly at night. Its large eyes and the black line running between them are distinctive.
Its short coat is gray or brown-mottled. The dark head has white crescent-shaped marks above the eyes and a black stripe running between them. The eyes are large, and pale orange fur extends over the neck, underside and inner limbs.
Researchers studied black-headed night monkeys at two sites in southeastern Peru and observed 14 groups. Every group was found in secondary tropical rainforest, often in areas dominated by native bamboo. Half of the sleeping sites they observed were in bamboo; others were in cane-like shrubs or tangled vines. The study recorded how the monkeys used several kinds of regrowing forest.
Density estimates were 19 individuals per square kilometre at one site and 50 at the other. Seeds from 12 plant species were recovered from fecal samples collected during two field seasons, including many from Cecropiaceae, Piperaceae and Moraceae. Groups were also observed in forest less than one kilometre from human settlements.
An extinction-risk assessment has not been added yet.
At both Peruvian sites, black-headed night monkeys were found in secondary forest, and half of the observed sleeping sites were in bamboo. Some groups lived in forest less than one kilometre from settlements. Seeds from 12 plant species, including many pioneer-plant families, were recovered from fecal samples.