Spix's night monkey is active at night. A feeding study in Peruvian river basins found fruit to be its main recorded food, with flowers and nectar also used.
Owl monkeys have gray-to-brown coats, large eyes, pale markings above and below the eyes, and dark stripes across the forehead. Spix’s night monkey is included in the gray-necked group within Aotus.
A 2026 study surveyed a 25-hectare secondary forest near Florencia in Caquetá, southern Colombia. From November 2022 to February 2023, researchers walked 20 line transects at night and recorded noisy night monkeys. They made 45 observation records, and the species was detected on 11 transects.
The estimated density was 47.3 animals per square kilometre, with an area-use probability of 0.56. Researchers observed the monkeys feeding on six plant species, including Xylopia frutescens and Euterpe precatoria. The authors reported the first density estimate and used-area estimate for this species at the north-western edge of its Amazonian distribution.
An extinction-risk assessment has not been added yet.
In secondary forest near Florencia, researchers recorded noisy night monkeys on 11 of 20 night-time transects. From 45 observations within the 25-hectare study area, they estimated a density of 47.3 individuals per square kilometre and an area-use probability of 0.56. The team also recorded feeding on six plant species. These measurements describe how the species used this reserve during the November–February survey period.