Until 1982, the genus Aotus was considered to have only one species, A. trivirgatus. After observing the large variance in reaction to diseases such as malaria amongst individuals of Aotus, it was suggested that the genus consisted of several species (Hershkovitz, 1983). Now, after much molecular research and many field studies, ten species are recognized, including A. nancymaae. However, some researchers recognize only one species still A. trivirgatus (Emmons, 1990).
Ma's night monkeys are domesticated and associated with human settlements in areas they inhabit.
Aotus nancymaae are very vocal. To remain in constant contact, groups of A. nancymaae constantly use a sequence of squeaks, whistles, and trills. Although this gives the group's position away, it allows for vital information to be passed rapidly through the group (Eisenberg and Redford, 1999, Moynihan, 1976). A slight raise in pitch allows for the communication of danger from predators (Eisenberg and Redford, 1999). Since communication is constant, all individuals in the group are aware of the warning and what it means.
These auditory signals are also used for territorial reasons. In defending a territory, individuals, usually juveniles, emit a series of squeaks, whistles and trills for 30-40 minutes. Rival groups respond in kind for longer periods from a distance no closer than 25 feet (Aquino and Encarnacion, 1986b, Einsberg and Redford, 1999, Greenberg, 1999). This exchange is the primary method of showing ownership of a territory. Subadults and solitary adults also emit high pitched squeaking while near or passing through claimed territory. It is believed that this communication is used for the attraction of mates (Greenberg, 1999, Moynihan, 1976).
Aotus nancymaae use visual perception. Unlike many other nocturnal species, A. nancymaae lack a tapetum locitum, a light catching surface, in the eye. They also retain other diurnal characteristics such as the retention of several types of retinal receptors more useful in seeing higher light intensities. In order to see better at night, A. nancymaae have enlarged eyes allowing for more light to be received. Aotus nancymaae have developed accelerated nerve impulses to and from retinal receptors, allowing them to see more instantaneously. This allows for faster response times through sight, giving A. nancymaae the ability to see insects better and to improve perception while moving. An increased olfactory bulb indicates that smell is also used for perception (Greenberg, 1999).
Communication Channels: acoustic
Other Communication Modes: choruses ; scent marks
Perception Channels: visual ; tactile ; acoustic ; chemical
There is little information on the conservation status of A. nancymaae
US Federal List: no special status
CITES: appendix ii
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
There are no negative impacts of A. nancymaae on humans.
Ma's night monkeys are sometimes used in medical research (Greenberg, 1999).
Positive Impacts: research and education
Aotus nancymaae are frugivores and may help to disperse seeds to a small extent. Living in groups of 2 to 5 individuals and having a population density of 8 to 10 groups per square kilometer, the population density hardly exceeds 20 individuals pre square kilometer. With a low basal metabolic rate, A. nancymaae require little food per individual (Aquino and Encarnacion, 1986a, Eisenberg and Redford, 1999). Aotus nancymaae do not impact food sources substantially because of the combination between this low population density and low food consumption.
Strong defensive behaviors, both nocturnally and diurnally, make A. nancymaae less desirable prey (Bales, 1980, Eisenberg and Redfield, 1999, Moynhan, 1976). Being nocturnal, A. nancymaae share territory with diurnal species with little competition.
Ecosystem Impact: disperses seeds
Aotus nancymaae are frugivorous, but, on occasion, feed on insects. Aotus nancymaae feed off of the fruit and the nectar of flowers of trees and insects in the region. They forage near the top of the canopy (Emmons, 1990, Greenberg, 1999, Moynihan, 1976).
Animal Foods: insects
Plant Foods: fruit; nectar; flowers
Primary Diet: herbivore (Frugivore )
Aotus nancymaae (Ma’s night monkey) can be found in the north central Amazonian neotropics of northern Peru and western Brazil in South America. This species was once thought to belong to the species Aotus trivirgatus, whose range was believed to reach from southern Central America to South America.
Biogeographic Regions: neotropical (Native )
Although considered habitat generalists (Greenberg, 1999), A. nancymaae are found primarily in lowland tropical rainforests. Aotus nancymaae prefer seasonally flooded forest regions because softer trees provide hollows and hanging shrubbery in which they hide and nest (Aquino and Encarnacion, 1986a, Greenberg, 1999). At night, while active, they occupy the upper levels of the canopy while foraging on fruits and flowers. During the day, they reside within the lower canopy of the forest, remaining inactive. Strongly arboreal, A. nancymaae do not naturally move on the ground. It has only been when individuals were in emergency situations that terrestrial locomotion has been documented (Aquino and Encarnacion, 1986a, Moynihan, 1976).
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: forest ; rainforest
Not enough information can be found on the lifespan of A. nancymaae.
Aotus nancymaae are small monkeys with non prehensile tails. Their pelage is light grey to light brown. Belonging to the “red necked” subdivision of Aotus, these monkeys have reddish orange hair along the sides of the neck and the inner lining of the limbs and tail base (Eisenberg and Redford, 1999, Emmons, 1990). The tail has a black tip and hangs straight down, a distinctive characteristic of all Aotus species (Emmons, 1990). The fur is short, dense and soft (Moynihan, 1996). Aotus nancymaae have characteristically large eyes. Their hands are well developed for grasping, capable of more independent movement than other New World primates (Moynihan, 1976). A post caudal gland is present and enlarged in both sexes; this is used for marking territory. The genitalia of adult A. nancymaae are brightly colored and displayed (Aquino and Encarnacion 1986b).
Range mass: 550 to 950 g.
Average mass: 788 g.
Range length: 530 to 774 mm.
Average length: 637 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike
The toned down colors of the pelage of A. nancymaae is characteristic of many nocturnal species. This color scheme, along with being active only in the dark, makes it more difficult to see individuals. The large eyes and accelerated nerve signals allow A. nancymaae to see better and faster at night, allowing for better reaction to predator presence (Greenberg, 1999). Aotus nancymaae communicate constantly, allowing for individuals to know where each other are located and for notification of the presence of predators to be passed on quickly throughout the group (Eisenberg and Redford, 1999, Moynihan, 1976). The careful selection of sleeping nests is one more behavioral trait for predator evasion. Part of the criterion for choosing a nest is multiple exits for emergencies. This allows A. nancymaae to quickly evacuate their own nests without being cornered within (Aquino and Enccarnacion, 1986a).
There is little information about predation on A. nancymaae. It is speculated that because of their nocturnal nature, strong vocal behavior, and ability to find and defend sufficient shelter, A. nancymaae are a difficult prey to hunt (Aqunia and Encarnacion, 1986a, Greenberg, 1999). Large, arboreal snakes may be their primary predators.
Known Predators:
Aotus nancymaae live in small groups, consisting of a monogamous breeding pair and up to the three of their most recent offspring. When they reach adulthood, an individual is forced from its family group and wanders about seeking a mate (Aquino and Encarnacion, 1986b). To attract a mate, A. nancymaae individuals emit squeaks while traveling through occupied territories (Aquino and Encarnacion, 1986b, Greenberg, 1999, Moynihan, 1976). Females have an estrus cycle of about 19 days (Greenberg, 1999). Females give birth to one young or rarely two young at a time (Aquino and Encarnacion, 1986b, Greenberg, 1999); two young may be the result of a high availability of resources. Breeding pairs continue to mate throughout life.
Mating System: monogamous
Aotus nancymaae mate year round, but it is speculated that offspring are conceived dependent of the availability of resources. This results in seasonal breeding in the wild (Greenberg, 1999). The breeding pair is able to care for up to three offspring at a time. There are no accounts of infanticide (Aquino and Encarcion, 1986b, Bales, 1980, Greenberg, 1999). Aotus nancymaae give birth to young that are well developed at the time of birth. Weaning can take from one to three weeks after birth, with the young gaining independent mobility by week three. Juveniles remain with the group for up to two years (Aquino and Encarcion, 1986b, Greenberg, 1999).
Breeding interval: Aotus nancymaae give birth 1 to 2 times yearly.
Breeding season: Aotus nancymaae breed year round.
Range number of offspring: 1 to 3.
Average gestation period: 133 days.
Range weaning age: 12 to 15 days.
Average weaning age: 13 days.
Average time to independence: 18 days.
Range age at sexual or reproductive maturity (female): 211 to 400 days.
Range age at sexual or reproductive maturity (male): 211 to 400 days.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
Within the first week of birth, primary care is shared between the mother and father of the young. The mother provides milk and transportation while the father provides transportation and protection. After about the first week, primary care is given by the father. At this point, the only contact between mother and young is during feeding. When feeding is completed, the mother will bite the young until it returns to the father (Eisenberg and Redford, 1999, Greenberg, 1999).
The care provided by the father in A. nancymaae is highly involved. Young are allowed to cling to either the stomach or the back of the father until free mobility is achieved. During this time, the father protects the young while sharing food with it. Young lose contact with the father only while feeding on milk from the mother (Bales, 1980, Greenberg, 1999). After independent mobility is achieved, the strong bond between father and offspring remains. It has been observed that the father of Aotus grooms, nurtures, and protects the young until they gain full independence. Although not observed, it has been noted that the father of A. nancymaae most likely plays with the young (Bales, 1980).
Parental Investment: precocial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male)
Nancy Ma's night monkey (Aotus nancymaae) is a night monkey species from South America. It is found in Brazil and Peru. The species is named after Dr. Nancy Shui-Fong Ma.[3]
It is known in medical research as a model organism for studying the Duffy antigen. Nancy Ma's night monkeys have also been found to have an evolutionary pattern change in the hormone oxytocin. It was believed that all placental mammals had the same OXT amino acid chain until the discovery of a change in this New World monkey and others.[4]
Nancy Ma's night monkey (Aotus nancymaae) is a night monkey species from South America. It is found in Brazil and Peru. The species is named after Dr. Nancy Shui-Fong Ma.
It is known in medical research as a model organism for studying the Duffy antigen. Nancy Ma's night monkeys have also been found to have an evolutionary pattern change in the hormone oxytocin. It was believed that all placental mammals had the same OXT amino acid chain until the discovery of a change in this New World monkey and others.
