Aotus trivirgatus cover most of tropical South America. From north to south they are found from Panama to northern Argentina. From east to west their range extends from the mouth of the Amazon to its headwaters in Peru and Ecuador. (Macdonald 1997)

Biogeographic Regions: neotropical (Native )

Both males and females of Aotus trivirgatus are similar in size with a body length of 24 to 47 cm. Tail length ranges from 22 to 42 cm. Coats range from grizzled brown, gray or reddish backs and off white to orange undersides. Coat color changes from one geographical location to another and for this reason, among others, A. trivirgatus is often separated into many different species or sub-species by different researchers. Aotus trivirgatus is the only nocturnal primate of the neotropics [See comments below]. They have the largest olfactory bulbs and accessory olfactory bulbs of all the New World monkeys presumably due to their reliance on smell during nocturnal activity. They also have large brown/orange eyes. The distinctive markings of the face include a triangular black patch between the eyes and black stripes on the sides, framing their otherwise white face.

(Macdonald 1997, Hershkovitz 1983, Wright 1994)

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: sexes alike

Average mass: 800 g.

Average basal metabolic rate: 2.499 W.

• Terrestrial

Aotus trivirgatus can be found from sea level to 3200 feet elevation, in habitats ranging from rain forests and cloud forests to bordering savanna. They have a narrow range of temperature tolerance between 28 and 30 degrees C. They are arboreal creatures and are generally found traveling from one fruit tree to another throughout the season. Aotus trivirgatus is found to prefer large canopied fruit trees.

(Baer et al. 1994)

Terrestrial Biomes: forest ; rainforest

Aotus trivirgatus eat primarily fruits, insects, nectar and leaves. They will also complement their diet with lizards, frogs and eggs for protein. During times when food is scarce, they seek out mostly nectar, figs and insects. At this time of year they seem to have the advantage over similar sized diurnal species that were chased away from these food sources by larger diurnal monkey.

(Baer et al. 1994)

Animal Foods: amphibians; reptiles; eggs; insects

Plant Foods: leaves; fruit; nectar

Primary Diet: omnivore

Average lifespan

Status: captivity: 18.5 years.

Average lifespan

Status: captivity: 25.3 years.

Average lifespan

Status: wild: 20.0 years.

Average lifespan

Status: wild: 12.0 years.

Average lifespan

Status: captivity: 19.3 years.

Aotus trivirgatus live in monogamous pairs. There is evidence of long term pair bonding.

Mating System: monogamous

Aotus seem to rely most heavily on calls to find mates. Since calls are not common among Aotus trivirgatus, a hoot usually indicates a lone male or female looking for a mate. Copulations generally take place at night, though they have been observed in the day. Females give birth to only one offspring each year and rarely twins. Infants are large and precocial at birth. Gestation length is 133 days. Mating takes place around August and September such that infants are born in the season of high fruit production. (Baer et al. 1994, Macdonald 1997)

Average birth mass: 88.5 g.

Average gestation period: 142 days.

Average number of offspring: 1.

Average age at sexual or reproductive maturity (male)

Sex: male: 730 days.

Average age at sexual or reproductive maturity (female)

Sex: female: 821 days.

Males are the primary caregiver of infants. Care includes carrying, guarding, playing with and sharing food with infants. This demands a significant amount of energy, as the males carry infants up to four months of age and often lag behind the rest of the group. Mothers nurse their young every 2 to 3 hours. Infants are large in comparison to their parents' body mass and grow quickly. Infant size and growth might explain the evolutionary adaptation of monogamy and male parental care, since infants demand more care than a single mother can provide.

Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Protecting: Male); extended period of juvenile learning

Aotus trivirgatus are being threaten by extensive deforestation of the tropical rainforests of South America. They are sensitive to clear cutting as well as selective deforestation, because this limits the diversity of diets within each group's limited territory. Owl monkeys are also hunted for their meat, skins, skulls, and teeth. They are hunted primarily by subsistence hunters who have been forced to turn to these smaller monkeys for food because larger game is no longer available. Trade to the U.S. and other countries as lab animals and pets also diminished the populations in the 70's. Today government bans in most South American counties and the U.S. limit export and import, thus reducing the impact of trapping as a threat. Protected areas in many South American countries have also helped in the conservation of this species. Unfortunately, due to economic and political problems, bans on hunting, trapping and deforestation in many of these areas are not enforced. (Baer et al. 1994)

IUCN Red List of Threatened Species: least concern

Aotus trivirgatus have been used as a food source by many indigenous peoples of the neotropics. More recently they have proved invaluable as laboratory animals and have been used for various studies and experiments in testing human diseases and potential treatments. One example is the role that A. trivirgatus have had in testing antimalarial drugs, since they too can be carriers of the human malaria parasites. Commercially there is also a market for owl monkeys as pets. (Baer et al. 1994, Geiman and Meagher 1967)