Aotus nancymaae 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Primates Aotidae

Scientific Name: Aotus nancymaae Hershkovitz, 1983
Common Name(s):
English Nancy Ma’s Night Monkey, Ma's Night Monkey, Peruvian Red-necked Owl Monkey
Spanish Mono Nocturno, Musmuki
Taxonomic Notes:

The taxonomy of the genus Aotus has been a matter of academic dispute due to the wide number of different karyotypes reported without clear phenotypic distinctions between intra- and inter-population variations (Ruiz-Herrera et al. 2005, Defler and Bueno 2007). Fernandez-Duque et al. (2013), recognized 11 species, and 13 taxa. A preliminary study on the distribution of the Genus Aotus in the Southern Colombian Amazon confirms the presence of A. nancymaae in Colombian territory. The results suggest the existence of a historical distribution of A. nancymaae north of the Amazon River in Colombia, as well as of another population of A. nancymaae, not of historical lineage but probably introduced in Colombia in more recent times (Bloor et al. 2012). Ruiz-García et al. (2011) discuss interesting insights about the evolution of Aotus that is beyond the scope of this description of A. nancymaae. Nevertheless, their evidence suggests that (1) the red-necked/grey-necked split among the Aotus, posited by Hershkovitz (1983) is artificial, since Aotus nancymaae is more related to the grey-necked Aotus than to the other red-necked Aotus and that (2) Aotus vociferans is likely the origin of other modern Aotus species due to its high number of haplotypes and lowest number of chromosomes among the species of the genus. 

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2cd+3cd+4cd ver 3.1
Year Published: 2017
Date Assessed: 2017-03-24
Assessor(s): Maldonado, A., Guzman-Caro, D., Shanee, S., Defler, T.R. & Roncancio, N.
Reviewer(s): Cotton, A. & Schwitzer, C.
Contributor(s): Palacios, E. & Cornejo, F.M.

This species is listed as Vulnerable due to an inferred past and present decline of its population of more than 30% within three generations (25 years) through habitat loss and hunting throughout its range. The same rate of decline is also inferred in the future. In Peru, the species' habitat has suffered massive deforestation of ~35,000 ha/year and increasing (Llactayo et al. 2013, Shanee et al. 2013b). Agricultural expansion in the species' extent of occurrence (EOO) in Brazil is also severely reducing its habitat (Barona et al. 2010). The species is also commonly found in the illegal pet trade in Peru (Shanee et al. 2015). The long-term (~40 years) offtake at the Brazil-Colombia-Peru tri-border area, where 4,000 animals were trapped in a 24-month period for biomedical research (Maldonado et al. 2009), is reflected by the decrease of their populations mainly in Peru (Maldonado and Peck 2014). 

Previously published Red List assessments:

Geographic Range [top]

Range Description:

In the Brazilian-Peruvian Amazon, Aotus nancymaae occurs south of the Rio Amazonas, west from the Rio Jutaí. Its southern limit is in the headwaters of the Rio Jutai, stretching west in a line to cross the Río Javari at the level of the headwaters of the Río Tapiche, across the Ucayali basin to the upper Río Marañón (Hershkovitz 1983, Aquino and Encarnación 1988, 1994a). The northern boundary in Peru is the right bank of the Amazonas to the Río Marañón, occurring to the north of the Marañón between the ríos Tigre and Pastaza (Aquino and Encarnación 1994), invading the distribution of A. vociferans north of the Amazonas and Marañón. The western boundary of the species' distribution in Peru is the Andean foothills in San Martin up to ~1,000 m above sea level (Shanee et al. 2015). In Colombia, the distribution of A. nancymaae is uncertain owing to the existence of a possible endemic subpopulation and an introduced subpopulation. Bloor et al. (2012) report the species north of the Amazon River, west from San Juan de Atacuari, border with Peru. Maldonado and Peck (2014) reported the predicted distribution of A. nancymaae in Colombia, where the species has been released after malaria research. Although the species is present all along the Amazon River, the distribution of the endemic subpopulation is limited to the Loretoyacu River basin. In Colombia its distribution range is approximately 652 km2 (MADS 2015).

Countries occurrence:
Brazil (Amazonas); Colombia; Peru
Additional data:
Lower elevation limit (metres):60
Upper elevation limit (metres):1000
Range Map:Click here to open the map viewer and explore range.

Population [top]


Aquino and Encarnación (1986a, 1988) have estimated densities of 24.2 to 46.3 individuals/km² in northeastern Peru. Maldonado and Peck (2014) reported densities for north-western Peru in the localities of Chineria, Yahuma and Vista Alegre of 3.24 to 24.04 individuals/km². Roncancio (2013) presented density estimates of 23.9 individuals/km² in Naranjales, southwestern Colombia.

Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Yes
Population severely fragmented:No
Continuing decline in subpopulations:Yes

Habitat and Ecology [top]

Habitat and Ecology:

Nancy Ma’s Night Monkey is part of the red-necked group of night monkeys, with a diploid chromosome number of 54 (Ford 1994). They are found in flooded and un-flooded tropical forest. Higher population densities have been found in flooded forests owing to the availability of tree holes, their preferred sleeping sites. Lowland swamp, pre-montane forests up to ~1,000 m asl. and inundated dense vine tangles are also used by Aotus nancymaae (Shanee et al. 2015; Aquino and Encarnación 1986a,b; Fernandez-Duque et al. 2013). In the Tahuayo River (Peru), A. nancymaae had 21.4% of its sleeping sites in the shrub stratum of the understory, 64.3% in the lower story and 14.3% in the middle story. No sleeping sites were found in the upper story or in emergent trees for this species (Aquino and Encarnación 1986a).

Night monkeys are generally nocturnal: they are most active at dawn and dusk. They are omnivorous; their diet includes fruit, nectar and flowers (seasonally important for A. a. azarae in the Chaco), leaves, and small animal prey such as insects (Wright 1989, Fernandez-Duque 2007). Nancy Ma’s Night Monkeys live in small groups that range from two individuals in hunting areas of north-eastern Peru (Maldonado and Peck 2014) to an average of 3.4 individuals in the Rio Tahuayo, northwestern Peru (Aquino and Encarnación 1988).

They are socially monogamous, with extensive male care of offspring (Rotundo et al. 2002, 2005; Wright 1984, Wolowich and Evans 2007), living in small groups of an adult pair and offspring of different ages (infant, one or two juveniles and sometimes a subadult). There may be subadults that have left their natal groups or older adults which have been evicted from their groups by competitors (Fernandez-Duque and Huntington 2002, Fernandez-Duque 2004). Both sexes disperse. Night monkeys are territorial—groups occupy overlapping territories of 1-18 ha (depending on the species, location and level of habitat fragmentation) (Wright 1978, Fernandez-Duque 2007, Garcia and Braza 1987, Castaño et al. 2010, Shanee et al. 2013a). Wright (1994) and Fernandez-Duque (2007) review the behaviour and ecology of the genus.

A peak in births has been reported for A. nancymaae between December and March, during the rainy season, and age of first reproduction is approximately 40 months. Interbirth intervals in captive females are 9-11 months (Aquino et al. 1990, Fernandez-Duque et al. 2013).  In a social study conducted by Wolowich and Evans (2007) on a captive colony, they reported that A. nancymaae possess a unique composite of communicative behaviors. Most social interactions between mates consist of anogenital- and nose-sniffing, urine-rinking, and partner-marking with the subcaudal gland. They also reported the frequent use of a variety of potential chemical signals including scent-marking with their muzzles, sternal glands, and subcaudal glands as well as urinating and urine-washing.

In Captivity: Adult male weight averages 0.946±0.14 kg (n=4, range 0.750-1.08 kg), adult female weight 0.907±0.124 kg (n=6, range 0.706-1.05 kg) (S. Evans, unpubl., in Fernandez-Duque 2007).

Generation Length (years):8.35

Use and Trade [top]

Use and Trade: Since 1984 Aotus nancymaae has been traded illegally from Peru and Brazil to Colombia for malaria research and later released to the wild in Colombian territory (Maldonado et al. 2009, Ruiz-Garcia et al. 2013). Trapping permits for malaria research are granted by the regional environmental authority, Corpoamazonia, to the biomedical facility FIDIC, in Leticia, Colombia. SINCHI (the Research Institute for the Colombian Amazon) and the Genetics Laboratory of the Colombian National University – IGUN-UNAL - (CITES Scientific Authorities) conducted a pilot project to gather baseline information on the genetics and ecology of Aotus spp. where the FIDIC had been trapping and releasing animals. Results from the UNAL/SINCHI study confirmed the presence of A. nancymaae in Colombian territory and suggested the existence of a historical distribution of A. nancymaae north of the Amazon River, as well as of another population of A. nancymaae, not of historical lineage but probably introduced in Colombia in more recent times (Bloor et al. 2012). Bearing in mind the reduced distribution of this species in Colombia, ~652 km2, the study recommended the prohibition of extraction of A. nancymaae in Colombia (MADS 2015). Nonetheless, in August 2016 the regional environmental authority (Corpoamazonia) granted another research permit for the capture of 1,463 adult Aotus nancymaae for a period of 566 days (Svensson et al. 2016). The species is commonly found in Peruvian indigenous communities for exhibition to tourists and as pets (Maldonado and Waters 2017). In Peru A. nancymaae are regularly found in the illegal pet trade (Shanee et al. 2015). This species can easily be found for live sale or kept as pets in northern Peru in all areas of its range, but particularly in the Belen market of Iquitos, Peru as well as skins and stuffed animals sold as adornments. In local markets in Peru Aotus spp. sell for ~ Sol 40 (= US$ 13.00), but at international borders and coastal city markets prices are much higher (N. Shanee unpublished data).

Threats [top]

Major Threat(s):

In Peru, the species’ habitat in San Martin and Loreto has been largely reduced through conversion of forests for rice cultivation, pasture and more recently palm oil, with annual deforestation rates of between 30,000 and 35,000 ha, and deforestation rates in Loreto are accelerating (Llactayo et al. 2013, Shanee et al. 2013b). In Brazil, deforestation in Amazonas state is driven by the expansion of the agricultural frontier mainly for cattle pasture and soy-bean production (Barona et al. 2010).

Studies of illegal trade in primates for Peru have regularly encountered Aotus nancymaae in markets and other forms of trafficking (Shanee et al. 2015). Although quantitative estimates do not exist, it is suspected that this trade is having a negative effect on populations in large areas of this species’ distribution.

The extraction of night monkeys for malaria research is drastically affecting wild populations in the tri-border area of Brazil-Colombia-Peru. In Peru, densities range from 13.6 individuals/km2 in areas where animals are trapped (Maldonado and Peck 2014) to 46.3 individuals/km2 (Aquino and Encarnacion 1986a) where trapping does not occur. This might be the result of longterm extraction for the biomedical research market or a result of deforestation associated with destructive trapping methods. Although the impact is likely to mimic natural gap formation, of concern is that trees with appropriate nesting holes are targeted and lost in the process, which may have longterm impacts on night monkey population recovery (Maldonado and Peck 2014).

A permit granted in 2016 for the trapping of A. nancymaae in Colombia lacks information on the population status of this species. In addition, Colombian indigenous collectors resident in Peru were allowed to be part of the team of trappers, promoting the illegal trade between Peru and Colombia (Svensson et al. 2016).

Conservation Actions [top]

Conservation Actions:

This species occurs in the following protected areas:        

Jutaí-Solimões Ecological Station (287,101 ha) (in range).

Pacaya-Samiria Natural Reserve (2,080,000 ha) (Aquino and Encarnación 1994b)
Manu National park (1,532,806 ha) (Aquino and Encarnación 1994b)
Tamshiyacu-Tahuayo Communal Reserve (Aquino and Encarnación 1994b).

Its distribution range occurs in indigenous territories where local people are the official collectors of night monkeys for malaria research, and hunting is allowed (Maldonado and Peck 2014).

It is listed on Appendix II of CITES.

Amended [top]

Amended reason: This amended version of the assessment has been published in order to add an additional assessor, Guzman-Caro D.C, to the list of assessors.

Citation: Maldonado, A., Guzman-Caro, D., Shanee, S., Defler, T.R. & Roncancio, N. 2017. Aotus nancymaae (amended version of 2017 assessment). The IUCN Red List of Threatened Species 2017: e.T41540A121725532. . Downloaded on 24 September 2018.
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