PERUVIAN NIGHT MONKEY
Aotus miconax
Geographic Distribution and Habitat
Endemic to the country of Peru, the Peruvian night monkey (Aotus miconax), also called the Andean night monkey, the Peruvian owl monkey, and the red-necked owl monkey, is found in patches of shrinking forest in northeast and north central Peru, along Río Marañón and Río Huallaga. Tree clearing has resulted in a discontinuous habitat that often confines this New World monkey to fragmented areas of forest.
Peruvian night monkeys thrive in the Amazon rainforest’s higher altitudes, typically between 2,600 and 7,800 feet (792-2377 meters) above sea level, where the climate is considerably less humid than lower level altitudes. They can be found in the Peruvian cloud forests and the dense upper canopies of primary and secondary forests. They are equally at home in disturbed and secondary logged forests, and higher altitude montane forests.
The Peruvian night monkey is one of many in the Aotus family. Other night monkeys in the Aotus genus include the Azara's night monkey, Colombian night monkey, Nancy Ma's night monkey, black-headed night monkey, three-striped night monkey, and Spix's night monkey.
Endemic to the country of Peru, the Peruvian night monkey (Aotus miconax), also called the Andean night monkey, the Peruvian owl monkey, and the red-necked owl monkey, is found in patches of shrinking forest in northeast and north central Peru, along Río Marañón and Río Huallaga. Tree clearing has resulted in a discontinuous habitat that often confines this New World monkey to fragmented areas of forest.
Peruvian night monkeys thrive in the Amazon rainforest’s higher altitudes, typically between 2,600 and 7,800 feet (792-2377 meters) above sea level, where the climate is considerably less humid than lower level altitudes. They can be found in the Peruvian cloud forests and the dense upper canopies of primary and secondary forests. They are equally at home in disturbed and secondary logged forests, and higher altitude montane forests.
The Peruvian night monkey is one of many in the Aotus family. Other night monkeys in the Aotus genus include the Azara's night monkey, Colombian night monkey, Nancy Ma's night monkey, black-headed night monkey, three-striped night monkey, and Spix's night monkey.
Peruvian night monkey range, IUCN 2019
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Size, Weight, and Lifespan Adults can weigh up to 2.5 pounds (1.13 kg) and can measure up to 20 inches (50 cm) in length, including their tails. Unlike many other species of primates, this species does not exhibit any notable sexual dimorphism. Since little data on this species has been recorded, lifespan can be hard to estimate. Scientists have estimated that Peruvian night monkeys live to about 12-14 years in the wild and up to 20 years in captivity, similar to other species of night monkey. Appearance
The Peruvian night monkey is similar in appearance to other species of night monkey, sharing the requisite wide eyes for seeing at night that all species of night monkey possess. The Peruvian night monkey’s large brown irises ring large, black center pupils; above the eyes, the slight outline of brown eyebrows can be seen. On the center of the head and immediately surrounding the eyes, nose, and mouth is black lining. The rest of the face is covered with tufts of white fur. The throat and part of the underside are covered with orange fur that does not extend all the way down the underside or anywhere along the back. The rest of the body, including the tail, is brindled with dark or light brown colors. Their hands are dark brown and are not entirely covered with fur. They have long, slender hands and fingers. With a tail that is longer than the body and legs longer than the arms, this monkey is well equipped for balancing in the canopy. Long, narrow, claw-like digits of the hands and feet come equipped with padding that aids in grasping branches in the canopy. The tail can be used for balance and as an extra hand when needed. 
Photo credit: Gregory Slobirdr Smith/Flickr/ShareAlike
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What Does It Mean?Cloud forest:
A forest that contains a persistent or seasonal presence of low level clouds and mist. Endemic: Native or restricted to a certain area or country. Genus: Taxonomic rank used to describe the hierarchy of biological classification. Genus comes above species and below family. Primary forest: Refers to a forest that has withstood time with little to no disturbance Secondary forest: Forest that is considered to be second-growth, or regrown to a point where past disturbances are not noticeable. Secondary logged forest: A secondary forest that has been logged for timber and resources. Sexual dimorphism: Distinct differences in size and appearance between the sexes of an animals in addition to difference between the reproductive organs. |
Diet
Peruvian night monkeys are frugivorous, that is, they mainly eat fruits, nectar, and flowers, but they also supplement their diet with small insects. The canopy of the forest provides much of the Peruvian night monkey’s diet, however they occasionally travel to the lower levels of the forest for certain fruits and flowers.
Peruvian night monkeys are frugivorous, that is, they mainly eat fruits, nectar, and flowers, but they also supplement their diet with small insects. The canopy of the forest provides much of the Peruvian night monkey’s diet, however they occasionally travel to the lower levels of the forest for certain fruits and flowers.
Behavior and Lifestyle
As their name suggests, Peruvian night monkeys are almost entirely nocturnal. Equipped with extra-large eyes for seeing in the dark, these monkeys eat, travel, and socialize at night. Night monkeys are the only nocturnal New World primates.
As their name suggests, Peruvian night monkeys are almost entirely nocturnal. Equipped with extra-large eyes for seeing in the dark, these monkeys eat, travel, and socialize at night. Night monkeys are the only nocturnal New World primates.
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Daily Life and Group Dynamics
Peruvian night monkeys spend most of the day sleeping or at rest in the hollows of trees, vines, and on branches. Researchers have recorded a few brief time periods throughout the day when they are awake and alert, in which they forage or travel. Throughout the night, while other mammals are sleeping, Peruvian night monkeys forage freely for food with little competition. They travel through the top of the canopy unfettered, leaping from branch to branch, grasping with their padded hands and using their long tails for balance. There, they are relatively safe from pumas, snakes, large birds, and other predators who are not active at night. Their foraging range is limited and dependent upon how much moonlight is available. When the moon shines bright, these monkeys can travel far to forage for food. However, when there is little moonlight or heavy cloud coverage, they do not travel as far. They repeatedly travel the same routes for food. Researchers suggest that the Peruvian night monkey can recognize moonlight patterns, and are able to remember certain farther distance routes when the moonlight is at its brightest, suggesting that they have very good memory. They are able to travel about a half mile in length. Groups consist of one breeding pair (the parents) and their offspring. This group will live in and defend a small area. Sometimes other members will include individuals who have left their group or individuals who were even kicked out of their group (the outcasts). Peruvian night monkeys live in monogamous family groups, which indicates a unique social behavior unlike most other monkey species. The social patterns of the Peruvian monkey are distinct in that they do not exhibit types of social bonding such as grooming. Their social behavior is more so seen in communication with one another through “hoos” or “whoops” and play behavior. Fighting has also been observed as a form of social behavior. Their social behavior has been especially observed by researchers when the moon is at its brightest. |
Fun FactsNight monkeys are also referred to as "owl" monkeys due to their large eyes and nocturnal behavior. The cloud forest gets its name due to a thick layer of mist and fog that occurs at the top of the canopy, giving the appearance of clouds hovering within the trees and producing some breathtaking views. Peru is one of the most primate-species rich countries in the world, with over 32 known species! New sub-species of primates are still being found within the Peruvian Amazon today. |
Communication
Peruvian night monkeys have a wide variety of calls and vocalizations that are used to display different messages and meanings. Other communication methods include visual cues and body movement.
The most common vocalization is a loud "hoot" call (this high-pitched call has a "hoo" sound that has little harmonic structure but consists of sequences of tones repeated over and over again for about an hour). While both males and females use the “hoot” call to attract a mate, the call may sound different between the sexes.
The deep "whoop" or deep "grunt" is a series of 10-15 low notes that will eventually crescendo into a climax. While making these calls, Peruvian night monkeys will stiffen their legs, jump, and have an arched posture. This is used to defend fruit trees. Adults also use this type of call with other members of the group.
Posture is often used along with certain calls. However, posture alone can signify certain behaviors or communication, such as mating calls or aggressive behavior in a bipedal position. Night monkeys as a species are typically quadrupedal, meaning they use all four limbs to move. However, certain bipedal postures (meaning they stand on two legs) signify various communications, including the presence of predators or a mate.
Night monkeys will mark their path or territory by producing an oily secretion from the base of the tail and spreading it. This is similar to other species of night monkey and will help mark territory or activity routes.
Reproduction and Family
Peruvian night monkeys reach sexual maturity at two years old. Both males and females initiate sexual behavior and mating calls. Not much is known about the specific mating process. Sexual calling and vocalizations begin the act of copulation. Once two mates find each other suitable, the act of copulation will begin.
There is a gestation period of about 130 days, or roughly four months. There is no specific birthing season, but more births tend to happen at the beginning of the rainy season.
This species is monogamous, meaning that the individuals only have one partner at a time. This forms a co-parenting style for offspring. The males assume most of the parental care: carrying, feeding and instructing in feeding, playing, and protecting from danger. The father stops carrying the infant after about five months. The mother nurses the infant until it is about seven months old. The infant is independent after the first year of his life. Male offspring leave the group between two and three years of age, when he is ready to mate. This suggests that males play a significant role in family structure and reproduction roles, not only in taking care of the young, but in starting family units.
Peruvian night monkeys have a wide variety of calls and vocalizations that are used to display different messages and meanings. Other communication methods include visual cues and body movement.
The most common vocalization is a loud "hoot" call (this high-pitched call has a "hoo" sound that has little harmonic structure but consists of sequences of tones repeated over and over again for about an hour). While both males and females use the “hoot” call to attract a mate, the call may sound different between the sexes.
The deep "whoop" or deep "grunt" is a series of 10-15 low notes that will eventually crescendo into a climax. While making these calls, Peruvian night monkeys will stiffen their legs, jump, and have an arched posture. This is used to defend fruit trees. Adults also use this type of call with other members of the group.
Posture is often used along with certain calls. However, posture alone can signify certain behaviors or communication, such as mating calls or aggressive behavior in a bipedal position. Night monkeys as a species are typically quadrupedal, meaning they use all four limbs to move. However, certain bipedal postures (meaning they stand on two legs) signify various communications, including the presence of predators or a mate.
Night monkeys will mark their path or territory by producing an oily secretion from the base of the tail and spreading it. This is similar to other species of night monkey and will help mark territory or activity routes.
Reproduction and Family
Peruvian night monkeys reach sexual maturity at two years old. Both males and females initiate sexual behavior and mating calls. Not much is known about the specific mating process. Sexual calling and vocalizations begin the act of copulation. Once two mates find each other suitable, the act of copulation will begin.
There is a gestation period of about 130 days, or roughly four months. There is no specific birthing season, but more births tend to happen at the beginning of the rainy season.
This species is monogamous, meaning that the individuals only have one partner at a time. This forms a co-parenting style for offspring. The males assume most of the parental care: carrying, feeding and instructing in feeding, playing, and protecting from danger. The father stops carrying the infant after about five months. The mother nurses the infant until it is about seven months old. The infant is independent after the first year of his life. Male offspring leave the group between two and three years of age, when he is ready to mate. This suggests that males play a significant role in family structure and reproduction roles, not only in taking care of the young, but in starting family units.
Photo: Fanny M. Cornejo/Creative Commons
Ecological Role
Night monkeys are important seed disperses of the forest, and assist in the natural reproduction of vegetation through the seeds they eat and digest. These seeds spread through their feces. These monkeys also provide food for predators.
Night monkeys are important seed disperses of the forest, and assist in the natural reproduction of vegetation through the seeds they eat and digest. These seeds spread through their feces. These monkeys also provide food for predators.
Conservation Status and Threats
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The International Union for Conservation of Nature has the Peruvian night monkey listed as Endangered (IUCN, 2019). The population trend has been slowly decreasing for decades as their habitat has become severely fragmented.
The threat level was increased from from Vulnerable to Endangered in 2019 based upon a suspected population decline of more than 50% due to a corresponding decline in habitat quality, as well as ongoing exploitation that has impacted one previous generation (2010-2018) and will likely impact at least two subsequent generations (2019-2035). Peru, like much of the Amazon, has suffered rapid deforestation and clear cutting of its land in the last several decades. High altitude montane forest land was incentivized by the Peruvian government to grow its agriculture economy. The land is perfect for coffee plantations and other various agricultural crops. During a period of economic growth and expansion, the Peruvian government encouraged Peruvians to move into once unpopulated areas to develop agriculture such as coffee plantations. This migration of people into these areas resulted in clear cutting of the forest. This has had a severe impact on the forest, and has made the population of the Peruvian night monkey very fragmented. This caused restriction in the night monkey's habitat. The distribution of Peruvian night monkeys became restricted to smaller patches of forest. Increased human population into the Peruvian night monkey’s habitat has meant the construction of more roads and major highways, fragmenting the forest even more. |
Conservation Efforts
The Peruvian night monkey is found in several national parks and protected areas of land throughout the country, including Abiseo National Park, Cordillera de Colán, and Bosque de Proteccion Alto Mayo. These protected areas provide an assured haven within the fragmented forest that they inhabit. Conservation groups such as Conservation International offer educational material about all of Peru's primates, encouraging further protection and conservation. The populations that occur in these protected areas of land seem to be safe for now. Researchers have been able to identify populations of Peruvian night monkeys in areas outside of protected forest and have urged the Peruvian government to establish more zones of protected forest.
Research by nonprofits and academia have studied the status of the Peruvian Amazon and look to work with the Peruvian government to address its rapid deforestation and its effects on animals such as the Peruvian night monkey. La Dirección General Forestal y de Fauna Silvestre, a part of the department of Peruvian Agriculture, has developed a strategy to help maintain and manage the current status of its forests and of the animals that inhabit it.
The Peruvian night monkey is found in several national parks and protected areas of land throughout the country, including Abiseo National Park, Cordillera de Colán, and Bosque de Proteccion Alto Mayo. These protected areas provide an assured haven within the fragmented forest that they inhabit. Conservation groups such as Conservation International offer educational material about all of Peru's primates, encouraging further protection and conservation. The populations that occur in these protected areas of land seem to be safe for now. Researchers have been able to identify populations of Peruvian night monkeys in areas outside of protected forest and have urged the Peruvian government to establish more zones of protected forest.
Research by nonprofits and academia have studied the status of the Peruvian Amazon and look to work with the Peruvian government to address its rapid deforestation and its effects on animals such as the Peruvian night monkey. La Dirección General Forestal y de Fauna Silvestre, a part of the department of Peruvian Agriculture, has developed a strategy to help maintain and manage the current status of its forests and of the animals that inhabit it.
References:
- Cornejo, F., Rylands, A.B., Mittermeier, R.A. & Heymann, E. 2008. Aotus miconax. The IUCN Red List of Threatened Species 2008: e.T1802A7646111.
- Shanee, Sam, Noga Shanee, and Néstor Allgas-Marchena. "Primate surveys in the Maranon-Huallaga landscape, northern Peru with notes on conservation." Primate conservation 27 (2013): 3-11
- http://pin.primate.wisc.edu/factsheets/entry/owl_monkey
- https://www.theguardian.com/environment/2013/mar/19/peruvian-night-monkey-threatened
- http://www.arkive.org/andean-night-monkey/aotus-miconax/
- https://alltheworldsprimates.org/Members/Home.aspx
- https://theredddesk.org/countries/actors/forestry-and-wildlife-agency-peru
- Kinzey, Warren G. New World Primates. New York: Walter de Gruyter, INC, 1997.
- https://www.conservation.org/Pages/default.aspx
Written by John DeVreese, January 2018
