The night monkeys, also known as the owl monkeys or douroucoulis, are the members of the genus Aotus of New World monkeys (monotypic in family Aotidae). The only nocturnal monkeys, they are native to Panama and much of tropical South America. Night monkeys constitute one of the few monkey species that are affected by the often deadly human malaria protozoan Plasmodium falciparum, making them useful as non-human primate experimental subjects in malaria research.
Until 1983, all night monkeys were placed into only one (A. lemurimus) or two species (A. lemurinus and A. azarae). Chromosome variability showed that there was more than one species in the genus and Hershkovitz (1983) used morphological and karyological evidence to propose nine species, one of which is now recognised as a junior synonym. He split Aotus into two groups: a northern, gray-necked group (A. lemurinus, A. hershkovitzi, A. trivirgatus and A. vociferans) and a southern, red-necked group (A. miconax, A. nancymaae, A. nigriceps and A. azarae). Arguably, the taxa otherwise considered subspecies of A. lemurinus – brumbacki, griseimembra and zonalis – should be considered separate species, whereas A. hershkovitzi arguably is a junior synonym of A. lemurinus. A new species from the gray-necked group was recently described as A. jorgehernandezi. As is the case with some other splits in this genus, an essential part of the argument for recognizing this new species was differences in the chromosomes. Chromosome evidence has also been used as an argument for merging "species", as was the case for considering infulatus a subspecies of A. azarae rather than a separate species. Fossil species have (correctly or incorrectly) been assigned to this genus, but only extant species are listed below.
Night monkeys have large brown eyes; the size improves their nocturnal vision increasing their ability to be active at night. They are sometimes said to lack a tapetum lucidum, the reflective layer behind the retina possessed by many nocturnal animals. Other sources say they have a tapetum lucidum composed of collagen fibrils. At any rate, night monkeys lack the tapetum lucidum composed of riboflavin crystals possessed by lemurs and other strepsirrhines, which is an indication that their nocturnalitiy is a secondary adaption evolved from ancestral diurnal primates.
Their ears are rather difficult to see; this is why their genus name, Aotus (meaning "earless") was chosen. There is little data on the weights of wild night monkeys. From the figures that have been collected, it appears that males and females are similar in weight; the heaviest species is Azara's night monkey at around 1,254 grams (2.765 lb), and the lightest is Brumback's night monkey, which weighs between 455 and 875 grams (1.003 and 1.929 lb). The male is slightly taller than the female, measuring 346 and 341 millimetres (13.6 and 13.4 in), respectively.
Night monkeys can be found in Panama, Colombia, Ecuador, Peru, Brazil, Paraguay, Argentina, Bolivia, and Venezuela. The species that live at higher elevations tend to have thicker fur than the monkeys at sea level. Night monkeys can live in forests undisturbed by humans (primary forest) as well as in forests that are recovering from human logging efforts (secondary forest).
A primary distinction between red-necked and gray-necked night monkeys is spatial distribution. Gray-necked night monkeys (Aotus lemurinus) are found north of the Amazon River, while the Red-necked group (Aotus azare) are localized south of the Amazon River. Red-necked night monkeys are found throughout various regions of the Amazon rainforest of South America, with some variation occurring between the four species of A. azare. A. nancymaae occurs in both flooded and unflooded tropical rainforest regions of Peru, preferring moist swamp and mountainous areas. This species has been observed nesting in regions of the Andes and has recently been introduced to Colombia, likely as a result of post-research release into the community. A. nigriceps is also found mainly in the Peruvian amazon (central and upper amazon), however its range extends throughout Brazil and Bolivia to the base of the Andes mountain chain . Night monkeys such like A. nigriceps, generally inhabit cloud forests; areas with consistent presence of low clouds with a high mist and moisture content which allows for lush and rich vegetation to grow year round, providing excellent food ans lodging sources. A. miconax, like A. nancymaae, is endemic to the Peruvian Andes however it is found at a higher elevation, approximately 800 -2400 m above sea level and therefore exploits different niches of this habitat. The distribution of A. azare, extends further towards the Atlantic Ocean, spanning Argentina, Bolivia and the drier, south western regions of Paraguay (Fernandez- Duque et al, 2008), however unlike the other Red-necked night owl species, it is not endemic to brazil.
During the daylight hours, Night monkeys rest in shaded tree areas. These species have been observed exploiting four different types of tree nests, monkeys will rest in; holes formed in the trunks of trees, in concave sections of branches surrounded by creepers and epiphytes, in dense areas of epiphyte, climber and vine growth and in areas of dense foliage. These sleeping sites provide protection from environmental stressors such as heavy rain, sunlight and heat. Sleeping sites are therefore carefully chosen based upon tree age, density of trees, availability of space for the group, ability of site to provide protection, ease of access to the site and availability of site with respect to daily routines. While Night monkeys are an arboreal species, nests have not been observed in higher strata of the rainforest ecosystem, rather a higher density of nests were recorded at low-mid vegetation levels. Night monkeys represent a territorial species, territories are defended by conspecifics through the use of threatening and agonistic behaviours. Ranges between Night monkey species often do overlap and result in interspecific aggressions such as vocalizing and chasing which may last up to an hour.
Night monkeys are primarily frugivorous (fruit eating species) as fruits are easily distinguished through the use of olfactory cues, but leaf and insect consumption has also been observed in the cathemeral night monkey species A. azare. A study conducted by Wolovich et al, indicated that juveniles and females were much better at catching both crawling and flying insects than adult males. In general, the technique used by night monkeys in insect capturing is to use the palm of the hand to flatten a prey insect against a tree branch and then proceed to consume the carcass. During the winter months or when food sources are reduced, night monkeys have also been observed foraging on flowers such as Tabebuia heptaphylla, however this does not represent a primary food source.
In night monkeys, mating occurs infrequently, however females are fertile year-round, with reproductive cycles range from 13-25 days. The gestation period for night monkey is approximately 117- 159 days but varies from species to species. Birthing season extends from September to March and is species dependant, with one offspring being produced per year; however, in studied conducted in captivity, twins were observed . Night monkeys reach puberty at a relatively young age, between 7- 11 months and most species attain full sexual maturity by the age of 2 years of age. A. azare represents an exception reaching sexual maturity by the age of 4.
The name "night monkey" comes from the fact that all species are active at night and are, in fact, the only truly nocturnal monkeys (an exception is the subspecies Aotus azarae azarae, which is cathemeral). Night monkeys make a notably wide variety of vocal sounds, with up to eight categories of distinct calls (gruff grunts, resonant grunts, sneeze grunts, screams, low trills, moans, gulps, and hoots), and a frequency range of 190-1,950 Hz. Unusual among the New World monkeys, they are monochromats, that is, they have no colour vision, presumably because it is of no advantage given their nocturnal habits. They have a better spatial resolution at low light levels than other primates, which contributes to their ability to capture insects and move at night. Night monkeys live in family groups consisting of a mated pair and their immature offspring. Family groups defend territories by vocal calls and scent marking.
The night monkey is socially monogamous, and all night monkeys form pair bonds. Only one infant is born each year. The male is the primary caregiver, and the mother only carries the infant for the first week or so of its life. This is believed to have developed because it increases the survival of the infant and reduces the metabolic costs on the female. Adults will occasionally be evicted from the group by same-sex individuals, either kin or outsiders.
The family Aotidae is the only family of nocturnal species within the suborder Anthropoidea. While the order primates is divided into prosimians; many of which are nocturnal, the anthropoids possess very few nocturnal species and therefore it is highly likely that the ancestors of the family Aotidae did not exhibit nocturnality and were rather diurnal species. The presence of nocturnal behavior in Aotidae therefore exemplifies a derived trait; an evolutionary adaptation that conferred greater fitness advantages onto the night monkey. Night monkey share some similarities with nocturnal prosimians including low basal metabolic rate, small body size and good ability to detect visual cues at low light levels. Their responses to olfactory stimulus are intermediate between those of the prosimians and diurnal primate species, however the ability to use auditory cues remains more similar to diurnal primate species than to nocturnal primate species. This provides further evidence to support the hypothesis that nocturnality is a derived trait in the family Aotidae.
As the ancestor of Aotidae was likely diurnal, selective and environmental pressures must have been exerted on the members of this family which subsequently resulted in the alteration of their circadian rhythm to adapt to fill empty niches. Being active in the night rather than during the day time, gave Aotus access to better food sources, provided protection from predators, reduced interspecific competition and provided an escape from the harsh environmental conditions of their habitat. To begin, resting during the day allows for decreased interaction with diurnal predators. Members of the family Aotidae, apply the predation avoidance theory, choosing very strategic covered nests sites in trees. These primates carefully choose areas with sufficient foliage and vines to provide cover from the sun and camouflage from predators, but which simultaneously allow for visibility of ground predators and permit effective routes of escape should a predator approach too quickly. Activity at night also permits night monkeys to avoid aggressive interactions with other species such as competing for food and territorial disputes; as they are active when most other species are inactive and resting.
Night monkeys also benefit from a nocturnal life style as activity in the night provides a degree of protection from the heat of the day and the thermoregulation difficulties associated. Although night monkey, like all primates are endothermic, meaning they are able to produce their own heat, night monkeys undergo behavioural thermoregulation in order to minimize energy expenditure. During the hottest points of the day, night monkeys are resting and therefore expending less energy in the form of heat. As they carefully construct their nests, night monkeys also benefit from the shade provided by the forest canopy which enables them to cool their bodies through the act of displacing themselves into a shady area. Additionally, finding food is energetically costly and completing this process during the day time usually involves the usage of energy in the form of calories and lipid reserves to cool the body down. Foraging during the night when it is cooler, and when there is less competition, supports the optimal foraging theory; maximize energy input while minimizing energy output .
While protection from predators, interspecific interactions, and the harsh environment propose ultimate causes for nocturnal behavior as they increase the species fitness, the proximate causes of nocturnality are linked to the environmental effects on circadian rhythm. While diurnal species are stimulated by the appearance of the sun, in nocturnal species, activity is highly impacted by the degree of moon light available. The presence of a new moon has correlated with inhibition of activity in night monkeys who exhibit lower levels of activity with decreasing levels of moon light. Therefore the lunar cycle has a significant influence on the foraging and a nocturnal behaviors of night monkey species.
Night monkeys are socially monogamous—they form a bond and mate with one partner. They live in small groups consisting of a pair of reproductive adults, one infant and one to two juveniles. These species exhibit mate guarding, a practice in which the male individual will protect the female he is bonded to and prevent other conspecifics from attempting to mate with her. Mate guarding likely evolved as a means of reducing energy expenditure when mating. As night monkey territories generally have some edge overlap, there can be a large number of individuals coexisting in one area which may make it difficult for a male to defend many females at once due to high levels of interspecific competition for mates. Night monkeys form bonded pairs and the energy expenditure of protecting a mate is reduced. Pair bonding may also be exhibited as a result of food distribution. In the forest, pockets of food can be dense or very patchy and scarce. Females, as they need energy stores to support reproduction are generally distributed to areas with sufficient food sources. Males will therefore also have to distribute themselves to be within proximity to females, this form of food distribution lends its self to social monogamy as finding females may become difficult if males have to constantly search for females which may be widely distributed depending on food availability that year.
However, while this does explain social monogamy, it does not explain the high degree of paternal care which is exhibited by these primates. After the birth of an infant, males are the primary carrier of the infant, carrying offspring up to 90% of the time. In addition to aiding in child care, males will support females during lactation through sharing their foraged food with lactating females. Generally, food sharing is not observed in nature as the search for food requires a great degree of energy expenditure, but in the case of night monkey males, food sharing confers offspring survival advantages. As lactating females may be too weak to forage themselves, they may lose the ability to nurse their child, food sharing therefore ensures that offspring will be well feed. The act of food sharing is only observed among species where there is a high degree of fidelity in paternity. Giving up valuable food sources would not confer an evolutionary advance unless it increased an individual’s fitness; in this case, paternal care ensures success of offspring and therefore increases the father’s fitness.
Recent studies have proposed that night monkeys rely on olfaction and olfactory cues for foraging and communication significantly more than other diurnal primate species. This trend is reflected in the species physiology; members of Aotidae possess larger scent perception organs than their diurnal counterparts. The olfactory bulb, accessory olfactory bulb and volume of lateral olfactory tract are all larger in Aotus than in any of the other new world monkey species . It is therefore likely that increased olfaction capacities improved the fitness of these nocturnal primate species; they produced more offspring and passed on these survival enhancing traits . The benefits of increased olfaction in night monkeys are two fold; increased ability to use scent cues has facilitated night time foraging and is also an important factor in mate selection and sexual attractivity.
As a substantial portion of the night monkey’s activities occurring during the dark hours of the night, there is a much lower reliance of visual and tactile cues. When foraging at night, members of the family Aotidae will smell fruits and leaves before ingesting to determine the quality and safety of the food source. As they are highly frugivorous and cannot perceive colour well, smell becomes the primary determinant of the ripeness of fruits and is therefore an important component in the optimal foraging methods of these primates . Upon finding a rich food source, night monkeys have been observed scent marking not only the food source, but the route from their sleeping site to the food source as well. Scent can therefore be used as an effective method of navigation and reduce energy expenditure during subsequent foraging expeditions . Night monkeys possess several scent glands covered by greasy hair patches, which secrete pheromones that can be transferred onto vegetation or other conspecifics. Scent glands are often located subcaudal, but also occur near the muzzle and the sternum. The process of scent marking is accomplished through the rubbing of the hairs covering scent glands onto the desired “marked item”.
Olfactory cues are also of significant importance in the process of mating and mate guarding. Male night monkeys will rub subcaudal glands onto their female partner in a process called “partner marking” in order to relay the signal to coexisting males that the female is not available for mating. Night monkeys also send chemical signals through urine to communicate reproductive receptivity. In many cases, male night monkeys have been observed drinking the urine of their female mate; it is proposed that the pheromones in the urine can indicate the reproductive state of a female and indicate ovulation. This is especially important in night monkeys as they cannot rely on visual cues, such as the presence of a tumescence, to determine female reproductive state. Therefore, olfactory communication in night monkeys is a result of sexual selection; sexually dimorphic trait conferring increased reproductive success. This trait demonstrates sexual dimorphism, as males have larger subcaudal scent glands compare to female counterparts and sex differences have been recorded in the glandular secretions of each gender. There is a preference for scents of a particular type; those which indicate reproductive receptivity, which increases species fitness by facilitating the production of offspring.
According to the IUCN (the International Union for the Conservation of Nature), two of four species of red-necked night monkeys are listed as vulnerable, A. nancymaae and A. miconax. A. nigriceps and A. azare listed as under least concern. Most night monkey species are threatened by varying levels of habitat loss throughout their range, caused by agricultural expansion, cattle ranching, logging, armed conflict, and mining operations. To date, it is estimated that more than 62 % of the habitat of A. miconax has been destroyed or degraded by human activities. However, some night monkey species have become capable of adapting exceptionally well to anthropogenic influences in their environment. Members of the A. miconax species have been observed thriving in small forest fragments and plantation or farmland areas, however this is likely possible given their small body size and may not be an appropriate alternate habitat option for other larger night monkey species. Studies have already been conducted into the feasibility of agroforestry; plantations which simultaneously support local species biodiversity . In the case of A. miconax, coffee plantations with introduced shade trees, provided quality habitat spaces. While the coffee plantation benefited from the increased shade—reducing weed growth and desiccation, night monkeys used the space as a habitat, a connection corridor or stepping stone area between habitats that provided a rich food source. However, some researchers question the agroforestry concept, maintaining that monkeys are more susceptible to hunting, predator and pathogens in plantation fields, thus indicating the need for further research into the solution before implementation.
Night monkeys are additionally threatened by both national and international trade for bushmeat and domestic pets. Since 1975, the pet trade of night monkeys has been regulated by CITES (the Convention on International Trade in Endangered Species). In the last forty years, nearly 6,000 live night monkeys and more than 7,000 specimens have been traded from the nine countries which they call home. While the restrictive laws put into place by CITES are aiding in the reduction of these numbers, 4 out of 9 countries, show deficiencies in maintaining the standards outlined by CITES (Svenssen, 2017). Increased attention and enforcement of these laws will be imperative for the sustainability of night monkey populations.
Use in biomedical research poses another threat to night monkey biodiversity. Species such as A. nancymaae, like human beings, are susceptible to infection by the Plasmodium falciparum parasite responsible for malaria. This trait caused them to be recommended by the World Health Organization as test subjects in the development of malaria vaccines. Up to 2008, more than 76 night monkeys died as a result of vaccine testing; some died from malaria, while others perished due to medical complications from the testing.
Increased research and knowledge of night monkey ecology is an invaluable tool in determining conservation strategies for these species and raising awareness for consequences of the anthropogenic threats facing these primates. Radio-collaring of free ranging primates proposes a method of obtaining more accurate and complete data surrounding primate behavior patterns. This in turn can aid in understanding what measures need to be taken to promote the conservation of these species. Radio collaring not only allows for the identification of individuals within a species, increased sample size, more detailed dispersal and range patterns, but also facilitates educational programs which raise awareness for the current biodiversity crisis. The usage of radio-collaring while potentially extremely valuable, has been shown to interfere with social group interactions, the development of better collaring techniques and technology will therefore be imperative in the realisation and successful use of radio collars on night monkeys.
The character Spider-Man in the 2019 film Spider-Man: Far From Home is offhandedly given the code name "Night Monkey" when he appears in the film in a new, all black suit. The character is referred to by this name several times throughout the film often to comedic effect.
Azara's night monkey (Aotus azarae), also known as the southern night monkey, is a night monkey species from South America. It is found in Argentina, Bolivia, Brazil, Peru and Paraguay. The species is monogamous, with the males providing a large amount of parental care. It is named after Spanish naturalist Félix de Azara. Although primarily nocturnal, some populations of Azara's night monkey are unique among night monkeys in being active both day and night. The species is listed as Least Concern on the IUCN Red List.Black-headed night monkey
The black-headed night monkey (Aotus nigriceps) is a night monkey species from South America. It is found in Bolivia, Brazil and Peru.Brumback's night monkey
Brumback's night monkey (Aotus brumbacki) is a species of night monkey found in Colombia. It has traditionally been considered a subspecies of gray-bellied night monkey, Aotus lemurinus. but it has recently been argued that it should be considered a separate species.Cytomegalovirus
Cytomegalovirus (CMV) (from the Greek cyto-, "cell," and megalo-, "large") is a genus of viruses in the order Herpesvirales, in the family Herpesviridae, in the subfamily Betaherpesvirinae. Humans and monkeys serve as natural hosts. There are currently eight species in this genus including the type species, Human betaherpesvirus 5 (HCMV, human cytomegalovirus, HHV-5), which is the species that infects humans. Diseases associated with HHV-5 include mononucleosis, and pneumonia. In the medical literature, most mentions of CMV without further specification refer implicitly to human CMV. Human CMV is the most studied of all cytomegaloviruses.Gray-bellied night monkey
The gray-bellied night monkey (Aotus lemurinus), also called the grey-legged douroucouli or lemurine owl monkey, is a small New World monkey of the family Aotidae. Native to tropical and subtropical forests of South America, the gray-bellied night monkey faces a significant threat from hunting, harvesting for use in pharmaceutical research and habitat destruction.Gray-handed night monkey
The gray-handed night monkey (Aotus griseimembra) is a species of night monkey formerly considered a subspecies of Gray-bellied night monkey of the family Aotidae. Its range consists of parts of Colombia and Venezuela. The exact classification of the gray-handed night monkey is uncertain. While some authors consider it a subspecies of the gray-bellied night monkey, A. lemurinus, other authors consider it a separate species, A. griseimembra.In Colombia, its range consists of the northern portion from the Sinú River (or perhaps further east) to the Venezuelan border, including the Sierra Nevada de Santa Marta and the Magdalena River, Cauca River and Sao Jorge River valleys. In Venezuela, it is found to the west and south of Maracaibo.The gray-handed night monkey is a relatively small monkey, with males weighing approximately 1,009 grams (35.6 oz) and females weighing about 923 grams (32.6 oz). It has short, tight fur. The fur on the back ranges from grayish brown to reddish brown. The belly is yellowish. The hair on the back of the hands and feet is the color of light coffee with darker hair tips, a key distinguishing feature from other A. lemurinus subspecies.The gray-handed night monkey is arboreal and nocturnal. It and the other members of the genus Aotus are the only nocturnal monkeys. Laboratory experiments indicated lower levels of activity even in lighting conditions consistent with a full moon. It is found in several types of forest, including secondary forest and coffee plantations, although one study indicated a preference for highly diverse forest. It lives in small groups of between two and six monkeys, most typically two to four, consisting of an adult pair and one infant and several juveniles and/or subadults. Groups are territorial, and groups occupy ranges that overlap only slightly. One study found a population density of 1.5 monkeys per square kilometer, while another found a density of 150 monkeys per square kilometer. The latter figure occurred in a forest remnant that had served as a refuge, which may account for the extremely high density.In common with other night monkeys, the gray-handed night monkey is one of the few monogamous monkeys. The monogamous pair generally gives birth to a single infant each year, although twins occasionally occur. The gestation period is about 133 days. The father carries the infant from the time it is one or two days old, passing it to the mother for nursing. Average interbirth interval for the mother is 271 days.The gray-handed night monkey is listed as "vulnerable" by the International Union for Conservation of Nature (IUCN). It is believed to be particularly threatened in Colombia. This is in part due to habitat loss, but also because many were captured in the 1960s and 1970s for malaria research.Hernández-Camacho's night monkey
Hernández-Camacho's night monkey (Aotus jorgehernandezi) is a species of night monkey of the family Aotidae. It was first described in 2007 by Thomas Defler and Marta Bueno. It has a gray neck and a white patch over each eye, separated by a black band. The fur on the chest, belly, lower arms and lower wrists is thick and white. It differs from other gray-necked night monkey species other than Brumback's night monkey in having 50 chromosomes.
It is believed to live in Colombia on the western slopes and foothills of the Andes, between Quindío and Risaralda. It is possible that it occurs in Tatamá Natural National Park. This range is currently also considered part of the range of the Panamanian night monkey. The Latin name honors the late Colombian biologist Jorge Hernández-Camacho.List of Central American monkey species
At least seven monkey species are native to Central America. An eighth species, the Coiba Island howler (Alouatta coibensis) is often recognized, but some authorities treat it as a subspecies of the mantled howler, (A. palliata). A ninth species, the black-headed spider monkey (Ateles fusciceps)is also often recognized, but some authorities regard it as a subspecies of Geoffroy's spider monkey (A. geoffroyi). In addition, two species of white-faced capuchin monkey have been generally recognized since the 2010s although some primatologists consider these to be a single species. Taxonomically, all Central American monkey species are classified as New World monkeys, and they belong to four families. Five species belong to the family Atelidae, which includes the howler monkeys, spider monkeys, woolly monkeys and muriquis. Three species belong to the family Cebidae, the family that includes the capuchin monkeys and squirrel monkeys. One species each belongs to the night monkey family, Aotidae, and the tamarin and marmoset family, Callitrichidae.
Geoffroy's spider monkey is the only monkey found in all seven Central American countries, and it is also found in Colombia, Ecuador and Mexico. Other species that have a widespread distribution throughout Central America are the mantled howler, which is found in five Central American countries, and the Panamanian white-faced capuchin (Cebus imitator), which is found in four Central American countries. The Coiba Island howler, the black-headed spider monkey, the Panamanian night monkey (Aotus zonalis), the Colombian white-faced capuchin (Cebus capucinus) and Geoffroy's tamarin (Saguinus geoffroyi) are each found in only one Central American country, Panama. The Central American squirrel monkey (Saimiri oerstedii) also has a restricted distribution, living only on part of the Pacific coast of Costa Rica and a small portion of Panama. El Salvador is the Central American country with the fewest monkey species, as only Geoffroy's spider monkey lives there. Panama has the most species, nine, as the only Central American monkey species that does not include Panama within its range is the Guatemalan black howler (Alouatta pigra).
Geoffroy's tamarin is the smallest Central American monkey, with an average size of about 0.5 kilograms (1.1 lb). The Central American squirrel monkey and Panamanian night monkey are almost as small, with average sizes of less than 1.0 kilogram (2.2 lb). The Guatemalan black howler has the largest males, which average over 11 kilograms (24 lb). The spider monkey species have the next largest males, which average over 8 kilograms (18 lb).One Central American monkey, the black-headed spider monkey, is considered to be Critically Endangered by the International Union for Conservation of Nature (IUCN). Geoffroy's spider monkey and the Guatemalan black howler are both considered to be Endangered. The Central American squirrel monkey had been considered endangered, but its conservation status was upgraded to Vulnerable in 2008. The Coiba Island howler is also considered to be vulnerable. The white-faced capuchins, the mantled howler and Geoffroy's tamarin are all considered to be of Least Concern from a conservation standpoint.Monkey watching is a popular tourist activity in parts of Central America. In Costa Rica, popular areas to view monkeys include Corcovado National Park, Manuel Antonio National Park, Santa Rosa National Park Guanacaste National Park and Lomas de Barbudal Biological Reserve. Corcovado National Park is the only park in Costa Rica in which all the country's four monkey species can be seen. The more accessible Manuel Antonio National Park is the only other park in Costa Rica in which the Central American squirrel monkey is found, and the Panamanian white-faced capuchin and mantled howler are also commonly seen there. Within Panama, areas to view monkeys include Darién National Park, Soberanía National Park and a number of islands on Gatun Lake including Barro Colorado Island. In addition, Geoffroy's tamarin can be seen in Metropolitan Natural Park within Panama City. In Belize, the easily explored Community Baboon Sanctuary was established specifically for the preservation of the Guatemalan black howler and now contains more than 1000 monkeys.List of Costa Rican monkey species
Four species of monkey are native to the forests of Costa Rica, the Central American squirrel monkey (Saimiri oerstedii), the Panamanian white-faced capuchin (Cebus imitator), the mantled howler (Alouatta palliata) and Geoffroy's spider monkey (Ateles geoffroyi). All four species are classified scientifically as New World Monkeys. Two of the species, the Central American squirrel monkey and the white-faced capuchin, belong to the family Cebidae, the family containing the squirrel monkeys and capuchins. The other two species belong to the family Atelidae, the family containing the howler monkeys, spider monkeys, woolly monkeys and muriquis. Each of the four species can be seen in national parks within Costa Rica, where viewing them in natural surroundings is a popular tourist attraction. The only park in which all four species can be seen is Corcovado National Park, on the Osa Peninsula.The smallest of the Costa Rican monkey species is the Central American squirrel monkey. Adult males average 0.8 kg (1.8 lb) and adult females average 0.7 kg (1.5 lb). The Central American squirrel monkey has the most restricted range of any Costa Rican monkey, living only in secondary forests and partially logged primary forests on the central and south Pacific coast of Costa Rica, and on the Pacific coast of Panama near the Costa Rican border. In 2008, the International Union for Conservation of Nature (IUCN) revised its conservation status to "vulnerable" after rating it "endangered" since 1982. The Central American squirrel monkey is most often seen in Manuel Antonio National Park and Corcovado National Park in Costa Rica.The other three species have wider ranges within Costa Rica, each being found in forests over much of the country. The white-faced capuchin, which has a range from Honduras to Ecuador, is the second smallest Costa Rican monkey. Adult males average 3.7 kg (8.2 lb) and adult females average 2.7 kg (6.0 lb). The mantled howler, with a range from Mexico to Ecuador, is the second largest monkey species in Costa Rica. Adult males average 7.2 kg (16 lb) and adult females average 5.4 kg (12 lb). Males make loud calls, especially at dawn and at dusk, that can be heard for several kilometers. Geoffroy's spider monkey, with a range from Mexico to Panama, is the largest of the Costa Rican monkeys, with males averaging 8.2 kg (18 lb) and females averaging 7.7 kg (17 lb). It has long, slim arms and a long, prehensile tail. The IUCN has rated the white-faced capuchin and mantled howler in the lowest conservation risk category of "least concern", and has rated Geoffroy's spider monkey as "endangered". Both the white-faced capuchin and the mantled howler are commonly seen in Costa Rica's parks.It is unknown why the Central American squirrel monkey has such a restricted range relative to the other Costa Rican monkey species. One theory is that the Central American squirrel monkey's ancestors arrived in Central America earlier than the ancestors of the other species. Under this theory, the squirrel monkey's ancestors arrived in Central America between 3 and 3.5 million years ago, but could not compete effectively when the ancestors of the other species arrived in Central America about 2 million years ago. The other species thus drove the squirrel monkey out of most of its original range. Another factor may be the Central American squirrel monkey's preference for lowland, coastal areas, which may make them more vulnerable to significant population declines due to occasional major hurricanes.Two other monkey species are sometimes reported as living in Costa Rica, Geoffroy's tamarin (Saguinus geoffroyi) and the Panamanian night monkey (Aotus zonalis or Aotus lemurinus zonalis). The western edge of Geoffroy's tamarin's known range is just west of the Panama Canal zone, about 200 kilometres (120 mi) from the Costa Rica border, and thus reports of it living in Costa Rica are most likely erroneous. Confusion may have resulted from the fact that over part of its range Geoffroy's tamarin is locally referred to as mono titi, which is a name also used for the Central American squirrel monkey in Costa Rica. Reports of the Panamanian night monkey living in Costa Rica are plausible, since the species is known to occur on the Caribbean coast of Panama not far from the Costa Rica border. However, reports of it living in Costa Rica have not been confirmed by scientists.List of Panamanian monkey species
At least six monkey species are native to Panama. A seventh species, the Coiba Island howler (Alouatta coibensis) is often recognized, but some authors treat it as a subspecies of the mantled howler, (A. palliata). An eighth species, the black-headed spider monkey is also often recognized, but some authorities regard it as a subspecies of Geoffroy's spider monkey. All Panamanian monkey species are classified taxonomically as New World monkeys, and they belong to four families. The Coiba Island howler, mantled howler, black-headed spider monkey and Geoffroy's spider monkey all belong to the family Atelidae. The white-faced capuchins and Central American squirrel monkey belong to the family Cebidae. the family that includes the capuchin monkeys and squirrel monkeys. The Panamanian night monkey belongs to the family Aotidae, and Geoffroy's tamarin belongs to the family Callitrichidae.
The mantled howler, the Panamanian night monkey, Geoffroy's spider monkey and the Panamanian white-faced capuchin all have extensive ranges within Panama. Geoffroy's tamarin also has a fairly wide range within Panama, from west of the Panama Canal to the Colombian border. The range of the black-headed spider monkey and Colombian white-faced capuchin within Panama are limited to the eastern portion of the country near the Colombian border. The Central American squirrel monkey only occurs within Panama in the extreme western portion of the country, near Costa Rica. It now has a smaller range within Panama than in the past, and is no longer found in its type locality, the city of David. As its name suggests, the Coiba Island howler is restricted to Coiba Island. The Azuero howler monkey (Alouatta coibensis trabeata or Alouatta palliata trabeata), which is considered a subspecies of either the Coiba Island howler or the mantled howler, is restricted to the Azuero Peninsula.The black-headed spider monkey is the largest Panamanian monkey with an average size of 8.89 kilograms (19.6 lb) for males and 8.8 kilograms (19 lb) for males. Geoffroy's spider monkey is the next largest, followed by the howler monkey species. Geoffroy's tamarin is the smallest Panamanian monkey, with an average size of about 0.5 kilograms (1.1 lb).One Panamanian monkey, the black-headed spider monkey, is considered to be critically endangered by the International Union for Conservation of Nature (IUCN), and Geoffroy's spider monkey is considered to be endangered. The Central American squirrel monkey was once considered endangered, but its conservation status was upgraded to vulnerable in 2008. The Coiba Island howler is also considered to be vulnerable. Three species, the mantled howler, the white-faeced capuchin and Geoffroy's tamarin are rated as "least concern" from a conservation standpoint.List of primates
List of primates contains the species in the order Primates and currently contains 16 families and 72 genera. See list of fossil primates for extinct species
and List of lemur species.List of primates of Colombia
The primates of Colombia include 41 extant species in 13 genera and five families. Additionally, 12 fossil species in 10 genera and five families have been identified in Colombia, mainly at the La Venta Lagerstätte of the Honda Group, mostly from the so-called "Monkey Unit", "Monkey Beds" or "Monkey Locality", the richest site for fossil primates in South America. As of 2013, of the 30 fossil primate species found in South America dating to the Late Oligocene (26 Ma) to the Pleistocene, twelve are described from the Honda Group. The genera Branisella, Caipora, Carlocebus, Chilecebus, Dolichocebus, Homunculus, Killikaike, Mazzonicebus, Proteropithecia, Protopithecus, Soriacebus, Szalatavus and Tremacebus have been discovered in Argentina, Bolivia, Brazil, Chile, Ecuador and Peru and are not known from Colombia. Additionally, Antillothrix, Insulacebus (both Hispaniola), Paralouatta (Cuba) and Xenothrix (Jamaica) were restricted to the Caribbean. The discovery of Perupithecus, described in 2015 from the Late Eocene (35-36 Ma) Santa Rosa fauna in the Yahuarango Formation of the Peruvian Amazon, pushes back the evolutionary lineage of New World primates.Nancy Ma's night monkey
Nancy Ma's night monkey (Aotus nancymaae) is a night monkey species from South America. It is found in Brazil and Peru.
It is known in medical research as a model organism for studying the Duffy antigen.Panamanian night monkey
The Panamanian night monkey or Chocoan night monkey (Aotus zonalis) is a species of night monkey formerly considered a subspecies of the gray-bellied night monkey of the family Aotidae. Its range consists of Panama and the Chocó region of Colombia. There are also unconfirmed reports of its occurrence in Costa Rica, especially on the Caribbean coast of Costa Rica. The species definitely occurs in the Atlantic lowlands of Panama close to the Costa Rica border.The exact classification of the Panamanian Night Monkey is uncertain. While some authors consider it a subspecies of the gray-bellied night monkey, A. lemurinus, other authors follow a study by Thomas Defler from 2001, which concluded that it is a separate species, A. zonalis.The Panamanian night monkey is a relatively small monkey, with males weighing approximately 889 grams (31.4 oz) and females weighing about 916 grams (32.3 oz). The fur on the back ranges from grayish brown to reddish brown. The belly is yellow. The hair on the back of the hands and feet is black or dark brown, which is a key distinguishing feature from other northern "gray-necked" Aotus species; also, its hair is shorter. Other distinguishing features relate to its skull, which has a broad braincase, a depressed interorbital region, and large molariform teeth.Like other night monkeys, the Panamanian night monkey has large eyes, befitting its nocturnal lifestyle. But unlike many nocturnal animal species, its eyes do not have a tapetum lucidum. Also like other night monkeys, it has a short tail relative to the body size.The Panamanian night monkey is arboreal and nocturnal. It and the other members of the genus Aotus are the only nocturnal monkeys. It is found in several types of forest, including secondary forest and coffee plantations. It lives in small groups of between two and six monkeys, consisting of an adult pair and one infant and several juveniles and/or subadults. Groups are territorial, and groups occupy ranges that overlap only slightly.Vocal, olfactory and behavioral forms of communication have all been recorded. At least nine vocal calls have been reported, including various types of grunts, screams, squeals, moans and trills. Males develop a scent gland near their tail at the age of about one year that is used for scent marking. Urine washing, in which urine is rubbed on the hands and feet, is also used. Behavioral communication appears to be less important than vocal and olfactory communication, but certain behavioral displays, including arched back displays, stiff legged jumping, urination, defecation and piloerection have been noted.The Panamanian night monkey generally walks on all four legs, although it is capable of leaping or running when necessary. It eats a variety of foods. In one study, on Barro Colorado Island in Panama, its diet was found to consist of 65% fruits, 30% leaves and 5% insects.In common with other night monkeys, the Panamanian night monkey is one of the few monogamous monkeys. The monogamous pair generally gives birth to a single infant each year, although twins occasionally occur. The gestation period is about 133 days. The father carries the infant from the time it is one or two days old, passing it to the mother for nursing.Although viewing monkeys is popular with tourists visiting Panama, the Panamanian night monkey's nocturnal habits make it less often seen than the other Panamanian monkey species. However, with a skilled guide it is possible to observe the Panamanian night monkey.Peruvian night monkey
The Peruvian night monkey (Aotus miconax), also known as the Andean night monkey, is a nocturnal New World monkey endemic to northern Peru. Adults weigh around 1 kg (2.2 lb) and measure up to 50 cm (20 in) in length. Its colour is grey to light brown with characteristic black and white markings on the face. The chest, belly and upper arms are orange tinged, however, to a lesser extent then Aotus nigriceps.
The species is one of the least known and possibly rarest Neotropical primates. This species is listed as vulnerable by the IUCN and endangered under Peruvian Law.The Peruvian night monkey is also one of the least studied of all primates. The only data that exists about this species are museum specimens, sighting records and very basic ecological information. The species is thought to inhabit areas of cloud forest at 900–2,800 m (3,000–9,200 ft) above sea level in the departments of Amazonas, Huanuco and San Martin, and in border regions of neighboring departments.Spix's night monkey
Spix's night monkey (Aotus vociferans) is a night monkey species from South America. It is found in Brazil, Colombia, Ecuador and Peru.
The Spix's night monkey is a small bodied monkey species usually having a mass of
around one kilogram. It belongs to the only nocturnal genus of New World primates
Aotus. This type of monkey can leap farther than most due to it having longer arms than
legs. The monkey averages 0.5 meters in height. The night monkey is considered to be
a new world monkey.The social behavior of the Aotus vociferans is group based. These groups
usually consist of breeding pairs and their offspring. This species has a
monogamous mating system. After the offspring are born, the father
becomes the main caretaker, only giving up the offspring for them to suckle. The offspring will
usually stay with their birth group until they reach two and a half to three and a half years
old. An exception to this if the male breeding partner is no longer present for any reason
(usually only caused by death), then the offspring may stay with its birth group for only
twelve weeks to the normal departure age. Social grooming in this species of monkey is
uncommon.The Aotus vociferans reproduce usually by giving birth to one offspring. Although, like with humans, there are cases of twins. The female breeding partner carries the offspring in interbirth for around one year. Both mating and birthing occur between November and
January. For this species, copulation attempts tend to be short and quick, starting with the male and female approaching one
another. Then the male performs a social sniff. During the original sniff, the female may
reciprocate but not always. Sexual intercourse usually consists of only three
to four thrusts by the male with him ejaculating on the final thrust.This species moves through the forest by swinging between horizontal branches
and uses all four limbs to grab branches. They may also leap from tree to tree.
This species communicates through voice, sight, smell, and touch. Vocally, this monkey has different sounds for different situations. To startle a potential predator the night monkey will “scream,” emitting a high pitched shriek. These monkeys use social sniffing to assess
potential breeding partners. They will also urinate on their hands and then rub it on different
surfaces to show sexual attraction. Aggressive males will usually arch their backs
with all of their limbs straightened. When in the presence of a predator the night monkey
will sway from side to side to try and deter the predator. A rejection bite is used as
tactile communication between mother and offspring after suckling or after around one
week old when contact is not welcome. Father and offspring also use a rejection bite when the offspring
reaches around 8 weeks when contact is not welcome.Thomas Defler
Thomas R. Defler (born 26 November 1941; Denver, Colorado) is a North American primatologist who lives and works in Colombia.
He earned his PhD from the University of Colorado at Denver in 1976 and then he moved to Colombia. Defler worked in eastern Colombia, in the Llanos until 1984 and then in the Amazonian Vaupés Department where he developed and lived in his research station, Estación Biológica Caparú until 1998 when he was obligated to flee from his research station by FARC guerrillas. He had run a primate rehabilitation center in Vaupes. He is the author of many papers about primates and of the books Primates de Colombia (2003), Primates of Colombia (2004) and Historia Natural de los Primates Colombianos (2010) . He also edited a monograph on woolly monkeys.Currently, he heads another Amazonian research station that he has developed in the southern Colombian Amazon, Estación Ecológica Omé, that is affiliated with the National University of Colombia and he teaches at the Bogotá campus of the same university. He and the Colombian biologist Marta Bueno are credited with first describing Hernández-Camacho's night monkey (Aotus jorgehernandezi) in 2007. Together with Javier Garcia, he led an expedition in which they discovered and described a new species of titi monkey, the Caquetá titi (Callicebus caquetensis). Using karyotypes, Defler has done work clarifying the taxonomy of various species of night monkey (Aotus). He has done field studies in the Colombian llanos and the Colombian Amazon on the white-fronted capuchin (Cebus albifrons), the brown woolly monkey (Lagothrix lagothricha), the black-headed uakari (Cacajao melanocephalus), the black titi (Callicebus lugens), the Lucifer titi (Callicebus lucifer), and the Venezuelan red howler (Alouatta seniculus) and has accomplished many primate censuses in different parts of eastern Colombia.Three-striped night monkey
The three-striped night monkey (Aotus trivirgatus), also known as northern night monkey or northern owl monkey, is one of several species of owl monkeys currently recognised. It is found in Venezuela and north-central Brazil.
Until 1983, all the owl monkeys were regarded as subspecies of Aotus trivirgatus, and all were referred to as douroucoulis. The use of the name douroucouli exclusively for the three-striped night monkey is not universally accepted; some authors use it for the entire genus, or for the grey-necked group of species within it (to which A. trivirgatus belongs).
Like other owl monkeys, the three-striped night monkey lives in woodlands including rain forest. It is mainly black, with striking white markings on its face. Its body size is 27–48 cm, and its tail is about the same length again. Adults weigh up to 1 kg. It has very large eyes, and is most active on moonlit nights, feeding on fruit, nuts, leaves, insects and other small invertebrates, and birds' eggs.
The three-striped night monkey forms pair bonds which are broken only by the death of one partner. It lives in family groups, with the immature young staying with their parents until sexual maturity at the age of 3 or 4. Normally only one infant is born, after a gestation period of a little over 4 months.
Extant primate families
Extant species of family Aotidae