Common name : Owl monkey
(New world monkey)
Life span: up to 20 years (captive) 11 years (wild)
(not sexually dimorphic)
Height: 1.14 ft (M), 1.12 ft (F)
Weight: 1.76 to 2.76 lb (all species, both sexes)
* There is very limited data on body size and weight for Aotus, most measurements from wild animals are extrapolated from only a few samples*
Separated into two groups based on their coloration, owl monkeys have gray-tan to brown bodies and either gray or red fur on the sides of their necks. 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. 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. 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.
The only nocturnal New World Monkey. Changes in the morphology of the eye and brain of owl monkeys reveal how specialized they have become to keep this nocturnal lifestyle. 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.
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
Food includes insects, animal prey, and fruit-deeming it to be herbivore
Total population: Unknown
Regions: Panama, Colombia, Ecuador, Peru, Brazil, Paraguay, Argentina, Bolivia
All of the gray-necked species live north of the Amazon River while the red-necked owl monkeys are found south of the Amazon.
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
Density of owl monkeys ranges from two to 16 groups per km²
Avg. Group Size- ranging between 2-5 individuals
Composition- one adult of each sex and young of various ages, however it’s not always a monogamous family
Mating System- lifelong monogamy in captivity but in the wild they separate regularly
Dominance Patterns & Practices- there is little in group aggression or agonistic behavior, however when a new adult is attempting to replace the current male or female there can be aggression which can lead to the permanent disfigurement or death of the resident monkey.
Territoriality– there is some inter-group aggression at home-range boundaries and meetings at fruit trees; neither groups wins and they retreat back to their own areas
Birth Seasonality- timed with ovulation, year round in captivity but peak in October to January in the wild
Gestation Length- 133 days
Number of Infants/Litter- nearly always single birth, but twins happen infrequently
Interbirth Interval- 12 months for captive and wild owl monkeys
Age of Sexual Maturity- 2-3 years old
How long are estrus swellings present?- only when ovulating and seeking a mate
Age at Weaning- between 22 and 46 days the infants get off of the carrier and begin to eat solid food, weaned completely by seven months
Age of Walking- by five months of age they are completely independent and no longer being carried at all
Age offspring leave their mothers- both males and females leave the group when they reach the age of sexual maturity, between 2 and 3 years old
Relationships between mothers and offspring exist for how many years?- all young leave the group, therefore their mothers, after 2-3 years
Evidence of infanticide- no evidence of infanticide 96% survival rate in captivity and 85.8% in the eild
What kind of infant/father relationship? – Adult males transfer food to children more often than adult females transfer food to children. Also the adult males and their children play by wrestling and chasing. Adult males carry the children because in case of predators they would be more likely to make it away, a female is handicapped because of how energetically taxing and nutritionally expensive lactating is.
Owl Monkeys communicate by using various signals including:
- Chemical signaling and scent marking
- Vocal indications
- Some visual signals
They have special glands under their tails which secrete special chemical signals that are used to display route paths, sexual indication, territory markings, and food locations. They also urinate on their hands and feet as they walk across branches for the same purpose as their tail glands.
They also have a unique throat “pouch” which can inflate to increase sound. This is not used to mark territory but merely communication between other owl monkeys. The owl monkey has been known to declare a fight with certain sounds by using this pouch, but that is only in direct circumstances. They also use their vocals to look for mates, and as young to ask for food.
The owl monkey has been known to give a few visual indicators of its emotions. Arching its back will indicate aggression. They will sway back and forth, usually while hanging from a branch, when spotted by predators – letting them know they see them. This is usually followed by evasive maneuvers to escape only if the predator does not become discouraged at being seen.
Owl monkeys have also been known to groom one another. They do not do this often, maybe once a month. This form of communication is often to consolidate bonds between one another.
Owl monkeys are not typically known for being the smartest primates. Therefore they have not passed along many behavioral traits that stand out. Most owl monkeys follow the same patterns, and because they are nocturnal they have freer roam than other primates. The parents will however teach their offspring how to smell for the ripest fruit.
Few disputes occur between owl monkeys. If they do it is usually small, resulting over a fight of fruit or territory and in the end there is usually no winner – but retreat to their own territory. Most aggression occurs when the moon is bright.
Owl Monkey Websites
Pictures all used under the Fair Use Act and is owned by:
Hourly Updated World News. N.p., 6 Feb. 2010. Web. 4 Feb. 2011. <http://www.iill.net/owl-monkey>.
Babb, P., E. Fernandez-duque, and T. Schurr. “AVPR1A Sequence Variation in Monogamous Owl Monkeys (Aotus azarai) and Its Implications for the Evolution of Platyrrhine Social Behavior. ” Journal of Molecular Evolution 71.4 (2010): 279. Health Module, ProQuest. Web. 6 Feb. 2011.
Cawthon Lang KA. 2005 July 18. Primate Factsheets: Owl monkey (Aotus) Taxonomy, Morphology, & Ecology . <http://pin.primate.wisc.edu/factsheets/entry/owl_monkey>. Accessed 2011 February 7.
Cawthon Lang KA. 2005 July 18. Primate Factsheets: Owl monkey (Aotus) Behavior . <http://pin.primate.wisc.edu/factsheets/entry/owl_monkey/behav>. Accessed 2011 February 7.
Juarez, C., M. Rotundo, W. Berg, and E. Fernández-duque. “Costs and Benefits of Radio-collaring on the Behavior, Demography, and Conservation of Owl Monkeys (Aotus azarai) in Formosa, Argentina. ” International Journal of Primatology 32.1 (2011): 69. Sciences Module, ProQuest. Web. 6 Feb. 2011.
Wolovich, C. K., et. al., Food Transfers to Young and Mates in Wild Owl Monkeys (Aotus azarai). American Journal of Primatology v. 70 no. 3 (March 2008) p. 211-21 http://vnweb.hwwilsonweb.com/hww/jumpstart.jhtml?recid=0bc05f7a67b1790e51f2120210eee01ae77c52e1a3513a4e32d4724fa6eede3bcce67d920cb50c2e&fmt=C