By Sarah Soderman
Geographic Range
Aotus lemurinus , commonly known as the owl monkey or night monkey, is found in Central and South America. They occur from Panama to northeastern Argentina, and from Peru and Equador to Guyana and Brazil.
Biogeographic Regions:
neotropical 
(native ).
Habitat
Owl monkeys occupy a variety of habitats. They are found from moist rainforest to dry scrub. Aotus lemurinus is most common in dense forest, where many vines are present. They can be found in all levels of the forest but are rarely found on the ground.
Terrestrial Biomes:
forest ; rainforest ; scrub forest .
Physical Description
(1.1 to 2.86 lbs)
Aotus lemurinus can be recognized by its small rounded head and owl-like face. Their brown eyes are large and round. Their thick white eyebrows lie below three black stripes on their head. A large black spot is found between their eyes. The eyeshine from these nocturnal monkeys is a bright reddish orange. Fur is dense and wooly and is usually grey in color. The color of the underparts of the monkey ranges from a pale yellow to a bright orange. Their tail is non-prehensile and mostly black, but may have brown or dark orange coloring on it. The tail always has a black tip. Their fingers are long and slender, with expanded pads on the tips. This monkey exhibits no sexual dimorphism. Weight ranges from 0.5 to 1.3 kg.
Some key physical features:
endothermic ; bilateral symmetry .
Reproduction
Aotus lemurinus is a monogamous mammal.
Mating systems:
monogamous .
Aotus lemurinus reaches sexual maturity at approximately 2.5 years of age. Females have an ovarian cycle which ranges from 13 to 19 days. There is no external indication of estrous. Males initiate reproduction. Reciprocal grooming has been observed in this species only prior to mating. Gestation period is 133 days. Females give birth to single young or sometimes twins.
Key reproductive features:
iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous .
The male and female both care for the young.
Parental investment:
precocial ; pre-fertilization (provisioning, protecting: female); pre-hatching/birth (provisioning: female, protecting: female); pre-weaning/fledging (provisioning: female, protecting: male, female).
Behavior
Aotus lemurinus is nocturnal and is most active several hours after dusk and before dawn. These monkeys live in small family groups consisting of between 2 to 5 members, including the adult pair and their offspring. During the day family groups will sleep either in tree hollows, vine covered trees, or dense brush. They are monogamous, and both parents play a role in raising their young. These monkeys are vocal and have various calls ranging from soft and low pitched grunts and clicks to louder, owl - like hoots. When danger is sensed they will produce a high - pitched shriek as an alarm signal. They are fairly sedentary.
Food Habits
Aotus lemurinus feeds at night, where they typically feed in the canopy. Their diet is broad, including fruit, flower nectar, foliage, and insects. These monkeys have also been known to feed on small birds and mammals.
Primary Diet:
omnivore .
Animal Foods:
birds; mammals; insects.
Plant Foods:
leaves; fruit; nectar.
Economic Importance for Humans: Positive
Aotus lemurinus is commonly used in biomedical research.
Conservation Status
IUCN Red List: [link]:
Vulnerable.
US Federal List: [link]:
No special status.
CITES: [link]:
Appendix II.
Aotus lemurinus populations have suffered due to collection for biomedical research and some hunting.
Contributors
Sarah Soderman (author), University of Michigan.
Phil Myers (editor), Museum of Zoology, University of Michigan.
