Owl monkey

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Suborder: Haplorrhini
Infraorder: Simiiformes
Family: Aotidae
Genus: Aotus
Species: A. azarae, A. hershkovitzi, A. lemurinus, A. miconax, A. nancymaae, A. nigriceps, A. trivirgatus, A. vociferans
Subspecies: A. a. azarae, A. a. boliviensis, A. a. infulatus, A. l. brumbacki, A. l. griseimembra, A. l. lemurinus, A. l. zonalis

Other names: douroucouli or night monkey; doeroecoeli (Dutch); douroucouli or singe de nuit (French); macaco da noite (Portuguese); cuatro ojos, marta, marteja, mono de noche, mono nocturno, or tutamono (Spanish); mirikina, nattapa, or negronattapa (Swedish); A. azarae: A. azarai; Azara’s night monkey; A. lemurinus: Colombian night monkey, gray-bellied night monkey, or lemurine night monkey; A. l. brumbacki: Brumback’s night monkey; A. l. griseimembra: grey-legged night monkey; A. hershkovitzi: Hershkovitz’s night monkey; A. miconax: Andean night monkey or Peruvian night monkey; A. nancymaae: A. nancymai; Nancy Ma’s night monkey or Peruvian red-necked owl monkey; A. nigriceps: black-headed night monkey or Peruvian night monkey; A. trivirgatus: northern night monkey, northern owl monkey, or three-striped night monkey; A. vociferans: noisy night monkey, Spix’s night monkey, or Spix’s owl monkey

Conservation status: please search the IUCN Red List.

Life span: 20 years (captive)
Total population: Unknown
Regions: Panama, Colombia, Ecuador, Peru, Brazil, Paraguay, Argentina, Bolivia
Gestation: 4.5 months (133 days)
Height: 346 mm (M), 341 mm (F)
Weight: 794 to 1254 g (M), 455 to 1246 g (F)

Owl monkey

The Genus Aotus used to contain only one species (Aotus trivirgatus) with ten subspecies, but in 1983, all ten subspecies were elevated to species level and subsequent genetic work has refined the taxonomy even more (Groves 2001). Within the genus, there are two groups of owl monkeys, the gray-necked (lemurinus and subspecies, hershkovitzi, trivirgatus, and vociferans), found north of the Rio Amazonas (Amazon River) and the red-necked (miconax, nancymaae, nigriceps, azarae and subspecies), found south of the Rio Amazonas (Groves 2001). Because this change in taxonomy was introduced fairly recently and is disputed, some published research continues to refer to the entire group as A. trivirgatus rather than distinguishing among species and subspecies. It may be necessary to generalize about some of the characteristics of owl monkeys because of the confusion of taxonomy in the literature in addition to the limited published information about this taxonomic group (Wright 1994; Sussman 2000).


Separated into two groups based on their coloration, karyotype, and geographic distribution, owl monkeys have gray-tan to brown bodies and either gray or red fur on the sides of their necks (Ford 1994). They have pale yellow to orange fur on their stomachs, underarms, and inner legs, light gray to white markings above and below their eyes, and three conspicuous, black stripes from the top of their head to either side of each eye and straight down the forehead between the eyes to the bridge of the nose (Ford 1994; Rowe 1996; Groves 2001). Their coats range in thickness and length depending on the altitudes at which they are found, with species living at higher elevations having thicker, shaggier coats than those living at sea level (Wright 1981; Groves 2001). They are unusual in their appearance compared to other primates because of their disproportionately large, brown eyes which have evolved as an adaptation to their nocturnal lifestyles. All owl monkeys are at least somewhat nocturnal and they are the only New World monkeys active at night (Wright 1994). While a nocturnal lifestyle is associated with primitive primates like prosimians, owl monkeys are not primitive but rather they re-evolved nocturnality from diurnal ancestors (Wright 1994; Rowe 1996). Changes in the morphology of the eye and brain of owl monkeys reveal how specialized they have become to keep this nocturnal lifestyle but also reveal structural commonalities between other diurnal primates (Rowe 1996). To see objects in low light levels, owl monkeys have evolved large eyeballs, their lenses have a more spherical shape than is seen in diurnal primates, and there are also more rods and fewer cones (Noback 1975). Though they do see in color, owl monkeys have less acute color vision than other primates. This is not a disadvantage as they are faster at locating and following moving objects at low light levels and have better spatial resolution at low light levels than other primates which helps them capture insects and move through arboreal habitat (Wright 1994).

Owl monkey on a branch

There is very limited data on body size and weight for Aotus, most measurements from wild animals are extrapolated from only a few samples. Owl monkeys are not sexually dimorphic so males and females are about the same size and weight (Wright 1994). Average male A. a. azarae weigh about 1254 g (2.76 lb) while females average 1246 g (2.75 lb). Wild A. a. boliviensis males weigh, on average 1180 g (2.60 lb) while females are slightly heavier, having an average weight of 1230 (2.71 lb) (Fernandez-Duque in press). The weights from one wild A. a. infulatus male and one female are 1190 g (2.62 lb) and 1240 g (2.73 lb), respectively, and data from one male and one female A. brumbacki reveal weights of 875 g (1.93 lb) and 455 g (1.00 lb) (Fernandez-Duque in press). Data from wild A. lemurinus reveal an average male weight of 920.7 g (2.03 lb) and average female weight of 859 g (1.89 lb). The weight of one male A. nigriceps was 875 g and the average weight of two females was 1040 g (2.29 lb). There is a fair amount of information available on the body weights of A. nancymaae and A. trivirgatus. A. nancymaae males weigh, on average, 794 g (1.75 lb) and females weigh 780 g (1.72 lb) while wild A. trivirgatus males weigh, on average 813 g (1.79 lb) and females average 736 g (1.62 lb) (Fernandez-Duque in press). The weights of wild A. vociferans and A. zonalis are also based on small sample sizes. Male A. vociferans weigh 697.5 g (1.54 lb) and there are no data for wild females while A. zonalis males have an average weight of 889 g (1.96 lb) and females weight 916 g (2.02 lb), on average (Fernandez-Duque in press). There are no data available for A. miconax.

Owl monkeys move quadrupedally on branches and vines in the forests in which they live and are skilled leapers, able to cross gaps in the canopy up to four meters wide (Wright 1984). The maximum recorded longevity for a captive owl monkey is 20 years (Rowe 1996). The only data on their longevity in the wild comes from an A. azarae population where it is known that a male has lived at least 11 years (Fernandez-Duque pers. comm.).


Aotus azarae | Aotus hershkovitzi | Aotus lemurinus | Aotus miconax | Aotus nancymaae | Aotus nigriceps | Aotus trivirgatus | Aotus vociferans

Owl monkeys are widely distributed across southern Central America and northern South America (Groves 2001). A. lemurinus subspecies are found in Panama, northern Colombia, and northwestern Venezuela while A. hershkovitzi ranges only in Colombia. The other gray-necked species include A. trivirgatus, which occupies a range extending from eastern Colombia and southern Venezuela into part of northern Brazil and A. vociferans, which is widely distributed across Colombia, northern Brazil, northern Peru, and eastern Ecuador (Groves 2001). All of the gray-necked species live north of the Amazon River while the red-necked owl monkeys are found south of the Amazon. A. miconax is limited to a very small region in northwestern Peru; A. nancymaae occupies a small region straddling the Peru-Brazil border and is sympatric with both red-necked (A. nigriceps) and gray-necked species (A. vociferans); A. nigriceps is found in Brazil and Peru, and A. azarae subspecies are found in Paraguay, Argentina, southern Bolivia, and Brazil (Groves 2001; Fernandez-Duque et al. 2001).

Little research has been conducted on Aotus in the wild probably primarily due to the difficulty of studying nocturnal primates (Sussman 2000). Research on owl monkeys requires not only specialized forest skills, including the ability to maneuver through the forest at night and good auditory and nocturnal visual skills, but radio-tracking equipment as well (Sussman 2000; Aquino & Encarnación 1994). Some of the intrepid owl monkey researchers and contributors to the knowledge of wild Aotus include Patricia Wright (Peru and Paraguay), Rolando Aquino and Filomeno Encarnación (Peru), and Eduardo Fernandez-Duque (Argentina). Captive studies of Aotus have been conducted at the New England Primate Research Center.


Aotus species widely inhabit primary, secondary, and remnant tropical forests as well as seasonally deciduous scrub forest, subtropical dry forest, and gallery forest from Panama to Argentina and Paraguay at a wide variety of elevations from sea level to 3200 m (10,498 ft) (Wright 1981; Aquino & Encarnación 1994; Fernandez-Duque et al. 2001). Temperatures at higher elevations can be as low as 5° C (41° F) and in the Chaco of Argentina, night temperatures as low as -5° C (23° F) are tolerated by Aotus (Fernandez-Duque 2003). They tend to inhabit areas of high plant species diversity with a relatively dense canopy and will forage at all canopy levels (Kinzey 1997). In Peru, they specifically prefer two types of habitats: lowland forest that is flooded seasonally or highland forest that is never flooded. In the flooded forest, where water can be as deep as seven meters (23.0 ft) during the rainy season, there is a predominance of trees with thickened trunks and branches that provide hollows used as sleeping sites, as well as pervasive growth of lianas and epiphytes, important plants used as sleeping sites and refuges (Aquino & Encarnación 1994). In Colombia, Aotus species are found in high, primary forests and in remnant and older secondary forests, but not in young secondary forests with low species diversity. In Argentina, Aotus is found in both high and low forests as well as gallery and island forests with dense canopies (Wright 1981; Fernandez-Duque et al. 2001). In Brazil, A. infulatus uses a variety of habitats including coastal forests with palm trees, mangroves, and gallery forest (de Sousa e Silva & Fernandes 1999). All of the habitats in which they are found exhibit seasonal patterns of rainfall and temperature changes, with the rainy season generally lasting from about September to about May and the dry season occurring during June through August (Wright 1981).


Aotus is the only nocturnal monkey. Adopting a system of nocturnal behavior seems disadvantageous to animals like primates that have a high dependence on vision: food, including insects, animal prey, and fruit, is more difficult to find at night, locomotion through the forest canopy is significantly more dangerous in dim light, and a different set of environmental conditions such as cooler temperatures, differences in humidity, competitors, and predators pose threats (Wright 1989). Despite these obstacles, the fossil record proves that owl monkeys assumed this nocturnal role from diurnal ancestors and, based on their wide geographical distribution, have been successful in exploiting this niche. Many of the ecological and behavioral characteristics of Aotus can be explained or at least linked to their unique pattern of life. Though most species of owl monkeys are nocturnal, A. a. azarae shows the particularly rare pattern of cathemeral activity in which it is regularly active during both daylight and nighttime hours (Fernandez-Duque 2003). Because of its range in the very seasonal Chaco of Argentina and Paraguay, the ability to forage during daylight hours is probably an adaptation to avoid activity on extremely cold, moonless nights (Fernandez-Duque 2003).

Owl monkey on a branch

Members of the genus generally leave their sleeping site about 15 minutes after sunset and return before sunrise each day (Wright 1986; Garcia & Braza 1993). After leaving the sleeping site, groups travel and feed until about midnight, when they stop to rest for 90 to 120 minutes. Owl monkeys are frugivores and supplement their diet with flowers, insects, nectar, and leaves (Wright 1989; 1994). They prefer small, ripe fruit when available and in order to find these, they forage in large-crown trees (larger than ten meters [32.8 ft]) (Wright 1986). Seasonal availability of fruit varies across environments. Aotus species in tropical forests eat more fruit throughout the year because it is more readily available compared to the dry forests where fruit is limited in the dry season and owl monkeys are more dependent on leaves (Wright 1994). It is difficult to quantify leaf and insect eating during the night, though, and researchers sometimes have to rely on fecal sample composition to project quantity and therefore importance to owl monkeys. Insect foraging occurs at dawn and dusk. Rather than seeking out insects in holes and crevices, owl monkeys are adept at grabbing flying insects out of the air or snatching them off of a branch (Wright 1989). They most often eat large orthopterans, moths, beetles, and spiders and probably specialize in these because of the insects’ rhythms. Moths are active at night, orthopterans call loudly at night, exposing their location, and beetles are active at night are easier making them easier to see (Wright 1989). After spending the night traveling, foraging, resting, and socializing, as dawn approaches owl monkeys increase their activity levels, and forage as they travel to either the same sleeping site from the previous day or another one within their home range (Wright 1981). Sleeping sites are either tree holes or thickets of dense foliage made up of lianas or epiphytes and, if they are big enough, may be shared with other nocturnal animals like bats (Aquino & Encarnación 1986; Garcia & Braza 1993). Owl monkeys spend most of their time foraging and sleeping above in the high canopy, above ten meters (32.8 ft) (Wright 1994).

Density of owl monkeys ranges from two to 16 groups per km² (.772 to 6.18 groups per square mile) (Fernandez-Duque et al. 2001). Home ranges of owl monkeys are smallranging between .031 and .175 km² (.012 and .068 mi²), depending on the species (Fernandez-Duque in press). The average nightly range is about of 708 m per night (.441 mi), but they use a larger area during the wet season, 829 m (.515 mi) per night and a smaller area during the dry season, 252 m (.157 mi) (Wright 1989). This use of space indicates that they spend more time resting and rely on fewer resources during the dry season, but resource availability is not the only factor influencing nightly travel distance. Nightly path length is also correlated with available light; the distance traveled is directly linked to the amount of moonlight on a given night. Owl monkeys travel twice as far on bright nights with full moons than on dark nights, and they concentrate their movement during the times of night with the most moonlight (Wright 1989; Fernandez-Duque 2003). Even though they do not travel as far, they still need to move on dark nights to find food and one adaptation to this need to forage is to travel the same routes repeatedly. They probably memorize routes and use chemical cues to help them find their way between food sites and sleeping sites (Wright 1989).

Owl monkey on a branch

Though owl monkeys are sympatric with other primates that use similar resources, they do not compete for access to resources because of their alternative schedules. Furthermore, non-primate nocturnal competitors are usually small-bodied (like bats) or forage alone or in pairs, not posing a significant source of competition (Wright 1989). Nocturnal predators do not usually eat monkeys, but some potential threats include owls, snakes, and felids. Diurnal raptors may pose a threat to owl monkeys if they are not well hidden in their sleeping sites (Wright 1989; 1994).


At any given time, there are about 150 to 200 million people worldwide infected with malaria and over a million children annually under the age of five die from this disease spread by infected mosquitoes (Dixson 1994). Owl monkeys have been successfully employed in biomedical research on malaria since the 1960s because of their natural resistance to the parasites that cause the disease (Ford 1994). Individuals of some species are intermittently removed from the wild to bolster captive colonies for research, breeding programs, and zoos, but effects on the total population are not significant and the population can recover after these “cropping” events (Aquino & Encarnación 1994).

Content last modified: July 18, 2005

Written by Kristina Cawthon Lang. Reviewed by Eduardo Fernandez-Duque.

Cite this page as:
Cawthon Lang KA. 2005 July 18. Primate Factsheets: Owl monkey (Aotus) Taxonomy, Morphology, & Ecology . <http://pin.primate.wisc.edu/factsheets/entry/owl_monkey/taxon>. Accessed 2020 July 15.


Owl monkeys live in closely-knit social groups of two to five individuals made up of one adult of each sex and young of various ages (Wright 1978; 1989; 1994; Fernandez-Duque et al. 2001). While researchers long assumed that owl monkeys lived in family groups, because there is always a single reproductive female and a single reproductive adult male that cares for the offspring, research from at least one species, A. azarae, reveals that the social structure may be more flexible than a monogamous family group. Frequently, resident adults are displaced by other same-sexed adults which then assume the breeding and care position in the social group. Males are equally as likely as females to be replaced (Fernandez-Duque in press). This process of replacement is characterized by high levels of physical aggression between the new adult attempting to displace the resident adult male or female and can lead to permanent disfigurement or even death of the resident owl monkey (Fernandez-Duque 2004).

Aotus groups move together cohesively, with individuals never more than ten meters (32.8 ft) from one another. Aggressive or agonistic behavior between group members is exceptionally rare (Wright 1981; 1994). Owl monkeys exhibit some inter-group aggression at their home-range boundaries and meetings at fruit trees on the perimeter of their territories include loud vocalizations, stiff-legged jumping displays, chasing, wrestling, and piloerection. These encounters usually only last about ten minutes, after which neither group “wins” but rather retreats into its own territory (Wright 1994). Peaks of social behavior, including inter-group aggression, occur most often when the moon is bright (Wright 1989). Other social behaviors seen in owl monkeys include grooming and play. Grooming is not often seen (less than one grooming bout per month occurs between adults within a group), but play is an important social behavior that is especially prevalent on bright nights. The adult male and his offspring play by wrestling and chasing, and often exhibit patterns of “pounce and retreat” and “rough and tumble” play four to five times per day in bouts of five to 20 minutes. Adult females rarely play with their offspring (Wright 1981).

Group of Owl monkeys on a branch

Because the primary social unit is the adult pair, both males and females disperse from their natal groups when they reach sexual maturity to find mating opportunities and start their own family groups. Both males and females leave the group between two and three years of age and range solitarily until they can find mates and establish a new territory (Fernandez-Duque & Huntington 2002; Fernandez-Duque in press). While establishment of new groups is not well-studied, subadult group members usually lag behind other group members during the month prior to their dispersal and spend more time away from the group, vocalizing and even sleeping in different trees, indicating they are preparing to leave the group and find a mate (Wright 1994; Fernandez-Duque & Huntington 2002). The timing of dispersal is also fairly uniform across groups, between August and January, and could either be related to the presence of new infants within the group or an attempt to find a mate before the mating season begins in May (Fernandez-Duque & Huntington 2002).


Almost all of the information about owl monkey reproductive characteristics comes from captive studies of the animal and new research on wild owl monkeys is beginning to reveal a very different picture. In captivity, Aotus has a monogamous mating system and the long-term bond between the adult pair probably lasts for life (Kinzey 1997). In the wild, the bonds between adult owl monkeys are dynamic and pairs separate regularly (Fernandez-Duque 2004). Male owl monkeys enter puberty at an early age, about one year old, when they begin to adopt physical characteristics of adult males including testicular growth and activation of the scent glands located under the base of the tail (Dixson 1994). As adults, male owl monkeys have extremely low sperm counts, probably as an adaptation to their monogamous mating system; only reproducing with one female, one time per year means it is unnecessary and energetically wasteful to produce high levels of sperm. Females are capable of reproducing as young as two years old, but normally do not give birth until about three years old (Gozalo & Montoya 1990). Physical examination of wild-caught A. a. azarae reveal that individuals do not reach adult body mass or have fully adult characteristics until about four years of age and age at first reproduction is at about five years (Fernandez-Duque in press). The ovarian cycle lasts about 16 days and menstruation does not occur in female owl monkeys. Mating occurs very infrequently both in the wild and in captivity and seems to be timed with ovulation (Dixson 1994; Fernandez-Duque et al. 2002). Once pregnant, gestation lasts 133 days and Aotus births are almost always singletons although twins are occasionally seen (Dixson 1994). In captivity, births occur year-round, but there is consistent peak in births from October to January. Among wild owl monkeys in the Argentinean Chaco, births coincide with the beginning of the rainy season, between late September and late November, and may be related to temperature and light conditions. Females that mate in April or May have a wide resource base available to support them during their energetically expensive pregnancy while infants born at the beginning of the rainy season will be mature enough to survive the extreme temperature drops seen in the dry season in May (Fernandez-Duque et al. 2002). Changes in photoperiod are probably the cue for mating to begin which is why similar peaks in births are seen both in the wild and in captivity (Fernandez-Duque et al. 2002). The interbirth interval is about 12 months for both wild and captive owl monkeys (Dixson 1994; Fernandez-Duque et al. 2002).


Two Owl monkey's

Among A. azarae studied in the Argentinean Chaco, rates of infant survival to six months are extremely high, around 96%, while in captivity, survival rates through the first year are about 85.8% (Gozalo & Montoya 1990; Fernandez-Duque et al. 2002). These high survival rates may be attributed to low incidences of predation and almost constant parental care. Owl monkey males are extremely involved in the socialization and care for dependent offspring. Researchers have long assumed that this pattern of parental care is seen because males are certain of their paternity because of their mating patterns and because of the potential benefits to the infant (Wright 1981). Genetic tests have not been conducted to confirm that male caregivers are fathers and until this is done, other explanations for this behavior should also be explored (Fernandez-Duque pers. comm.). Male owl monkeys that constantly carry dependent offspring may be better equipped to flee from predators or danger than a lactating female of equal size. Because lactation is nutritionally expensive and energetically taxing, females may lack the energy necessary to run with infants that are relatively large compared to their body size (Wright 1984). The infant, therefore, gains an advantage if being carried by an adult male compared to its mother.

Newborn owl monkeys weigh, on average, 96.5 g (3.40 oz) and instinctively ventrally cling to the mother. The infant will exhibit this pattern of attachment until about three to four weeks of age, when it will begin to cling dorsally to its carrier (Dixson 1994). Developmental stages have been observed in captivity. Starting on the first day of life, the father begins to carry the infant, and though he will carry the infant almost exclusively for the first 2 months of life, the mother carries and nurses the neonate in the first week of life (Wright 1984; Dixson 1994). After the first week, the mother only carries the infant when it nurses, approximately 10 to 20% of the time, the remaining 80 to 90% of its life is spent on the father (Wright 1986). Beginning as early as 22 days or as late as 46 days, infants get off the carrier and begin to eat solid food as a supplement to nursing (Dixson 1994). As they age, infants are carried increasingly less such that by five months of age, they are totally independent. As they gain this independence though, there are some conflicts between the father and infant starting at about four months; conflicts over carrying include the infant holding on to the father tightly while he attempts to bite or push the infant off. During this time, there is very little carrying by the father, but the infant still rides on his back as the group travels between trees that are between three and four meters apart (9.84 and 13.1 ft) (Wright 1984). Even though infants travel independently by five months of age, they are not weaned completely until about seven months and in the instance of any disturbance or stressor, they will return to the parents for support (Dixson 1994). Older siblings that are still in the group when an infant is born take turns carrying it, but they are limited to carrying during the first four weeks of life, after which the infant is too big for them to support (Wright 1984).


Owl monkeys communicate through chemical signaling and scent marking, vocalizing, and by using some visual cues (Wright 1994; Bolen & Green 1997). Specialized scent glands under the base of their tails secrete chemical signals that convey information to other individuals including sexual identification and route-marking from sleeping sites to food resources (Wright 1989; 1994). They also exhibit a behavior known as “urine washing” in which they urinate on their feet and hands and as they walk over branches, leaving a scented path (Wright 1981). Their honed sense of smell may also help them distinguish ripe from unripe fruits in an environment in which color is dulled (Wright 1989).

Unlike their highly developed sense of smell, the auditory system among owl monkeys is unspecialized compared to other primates. However, they do have a specialized throat pouch which inflates and increases the volume and power of calls (Wright 1981). They have not been observed giving a territorial call like other monogamous primates such as gibbons (Hylobates species), but their vocal repertoires may serve to reinforce bonding between individuals of a group as well as inter-group interactions at home range boundaries (Wright 1981). The aggressive call or “war whoop” of owl monkeys is a call consisting of a series of a dozen low notes or grunts which increase in volume and power into hoots; this call is exhibited by both sexes and heard only during direct conflict with another group. Subadult males and females use the same type of call in a shorter series of three to five hoots as a long-distance contact call when they are looking for a mate (Wright 1981; Kinzey 1997). The generalized alarm call of the owl monkeys is a series of “sneeze-grunts” while softer calls that sound like purrs are used to reinforce bonds between group members or alert them to desirable food sources. When infants express desire for food or contact to their parents, they squeak loudly (Wright 1981).

Content last modified: July 18, 2005

Written by Kristina Cawthon Lang. Reviewed by Eduardo Fernandez-Duque.

Cite this page as:
Cawthon Lang KA. 2005 July 18. Primate Factsheets: Owl monkey (Aotus) Behavior . <http://pin.primate.wisc.edu/factsheets/entry/owl_monkey/behav>. Accessed 2020 July 15.


For individual primate species conservation status, please search the IUCN Red List.
Also search the current scientific literature for primate conservation status (overall as well as for individual species), and visit CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora).

Conservation information last updated in 2005 follows, for comparison:

Owl monkey

The majority of Aotus species are widespread and abundant and are not threatened by extinction, but some have an increased or very high risk of extinction. Those species that are of concern are threatened in Colombia, Panama, Ecuador, and Peru, mostly because of rapid rates of habitat destruction in these countries and existing subpopulations with few mature adults. The problem is even further compounded by the fact that the taxonomy of the entire genus is debated and not fully understood. Geographical distributions of each species in Colombia need to be ascertained according to one taxonomic model before assigning conservation status to each species (Defler et al. 2003). Censuses and research on distribution are necessary for the species in Colombia and Panama as their abundance is not well understood. What is known about the habitats in which they live is that human habitat use is increasing as civil unrest plagues the country and there are no areas of enforced protection (Defler et al. 2003). Categorization by the IUCN, given the apparent lack of published data on conservation issues, general biology, and ecology of some of these species, is undertaken by the Primate Specialist Group, a panel of primate experts compiled to assess and evaluate the conservation status of all species of primates. These experts meet to assess the status of primates worldwide and the resulting classification is often the result of the judgment of an individual Specialist Group member, not because there is widespread information about the species (Hilton-Taylor 2000). The status of Aotus is a good example of how classification is assigned in the most prudent way possible by the Primate Specialist Group even in the absence of species-specific data.





Content last modified: July 18, 2005

Written by Kristina Cawthon Lang. Reviewed by Eduardo Fernandez-Duque.

Cite this page as:
Cawthon Lang KA. 2005 July 18. Primate Factsheets: Owl monkey (Aotus) Conservation . <http://pin.primate.wisc.edu/factsheets/entry/owl_monkey/cons>. Accessed 2020 July 15.

The following references were used in the writing of this factsheet. To find current references for Aotus, search PrimateLit.


Aquino R, Encarnación F. 1994. Owl monkey populations in Latin America: field work and conservation. In: Baer JF, Weller RE, Kakoma I, editors. Aotus: the owl monkey. San Diego (CA): Academic Pr. p 59-95.

Bolen RH, Green SM. 1997. Use of olfactory cues in foraging by owl monkeys (Aotus nancymai) and capuchin monkeys (Cebus apella). J Comp Psych 111(2): 152-8.

Owl monkey artwork

de Sousa e Silva Jr. J, Fernandes MEB. 1999. A northeastern extension of the distribution of Aotus infulatus in Maranhão, Brazil. Neotrop Prim 7(3): 76-9.

Defler TR, Rodríguez-M JV, Hernández-Camacho JI. 2003. Conservation priorities for Colombian primates. Prim Cons 19: 10-18.

Dixson AF. 1994. Reproductive biology of the owl monkey. In: Baer JF, Weller RE, Kakoma I, editors. Aotus: the owl monkey. San Diego (CA): Academic Pr. p 113-32.

Fernandez-Duque E. In press. The Aotinae: social monogamy in the only nocturnal haplorhines. Primates in Perspective. In: Bearder S, Campbell CJ, Fuentes A, MacKinnon KC, Panger M, editors. Primates in perspective. Oxford (UK): Oxford Univ Pr.

Fernandez-Duque E. 2003. Influences of moonlight, ambient temperature, and food availability on the diurnal and nocturnal activity of owl monkeys (Aotus azarai). Behav Ecol Sociobiol 54(5): 431-40.

Fernandez-Duque E. 2004. High levels of intra-sexual competition in sexually monomorphic owlm nokeys [Abstract]. Folia Primatol 75(Suppl. 1): 260.

Fernandez-Duque E, Huntington C. 2002. Disappearances of individuals from social groups have implications for understanding natal dispersal in monogamous owl monkeys (Aotus azarai). Am J Primatol 57(4): 219-25.

Fernandez-Duque E, Rotundo M, Ramirez-Llorens P. 2002. Environmental determinants of birth seasonality in night monkeys (Aotus azarai) of the Argentinean Chaco. Int J Primatol 23(3): 639-56.

Fernandez-Duque E, Rotundo M, Sloan C. 2001. Density and population structure of owl monkeys (Aotus azarai) in the Argentinean Chaco. Am J Primatol 53(3): 99-109.

Ford SM. 1994. Taxonomy and distribution of the owl monkey. In: Baer JF, Weller RE, Kakoma I, editors, Aotus: the owl monkey. San Diego (CA): Academic Pr. p 1-57.

Garcia JE, Braza F. 1993. Sleeping sites and lodge trees of the night monkey (Aotus azarae) in Bolivia. Int J Primatol 14(3): 467-77.

Gozalo A, Montoya E. 1990. Reproduction of the owl monkey (Aotus nancymai) (Primates: Cebidae) in captivity. Am J Primatol 21(1): 61-8.

Groves C. 2001. Primate taxonomy. Washington DC: Smithsonian Inst Pr. 350 p.

Hilton-Taylor C, compiler. 2000. 2000 IUCN Red List of threatened species. Gland (Switzerland): IUCN. 61 p.

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Content last modified: July 18, 2005


Photo: Luiz Claudio Marigo
Photo: Luiz Claudio Marigo
Photo: Marilyn Cole
Photo: Marilyn Cole
Photo: Primates in Art & Illustration Collection
Photo: Roy Fontaine

Aotus azarae azarae
Photo: Eduardo Fernandez Duque

Aotus azarae boliviensis
Photo: Rosie Bolen
Aotus azarae boliviensis
Photo: Rosie Bolen

Aotus nancymaae
Photo: Rosie Bolen

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