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
Species Authority: Hershkovitz, 1983
Common Name(s):
English Nancy Ma’s Night Monkey, Peruvian Red-necked Owl Monkey, Ma's Night Monkey
Spanish Macaco Da Noite, Mono Nocturno
Taxonomic Notes: It is doubtful that the current taxonomy provides a true picture of the diversity of the genus Aotus. Ruiz-Herrera et al. (2005) reported that cytogenetic studies have characterized 18 different karyotypes with diploid numbers ranging from 46 to 58 chromosomes. The taxonomy of the night monkeys essentially follows the revision by Hershkovitz (1983), with some modifications for the Colombian and Central American forms.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor(s): Cornejo, F. & Palacios, E.
Reviewer(s): Mittermeier, R.A. & Rylands, A.B. (Primate Red List Authority)
This species is listed as Least Concern due to its wide range, suspected large populations, and because there are no major threats believed to be resulting in a significant population decline at present.
Previously published Red List assessments:

Geographic Range [top]

Range Description: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 1994a, 1988). 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 1994a), invading the distribution of A. vociferans north of the Amazonas and Marañón.
Countries occurrence:
Brazil (Amazonas); Peru
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Aquino and Encarnación (1986a, 1988) have estimated densities of 24.2 to 46.3 individuals/km² in north-eastern Peru. Aquino and Encarnación (1994b) reviewed population structure and densities for the genus.
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:Night monkeys typically occur in primary and secondary forest (including disturbed forest and selectively logged forest), seasonally flooded and terra firma, lowland forest (Aquino and Encarnación 1986a,b, 1988, 1994a,b; Defler 2004). Aquino and Encarnación (1994b) reviewed the habitat and forest preferences of the genus.

Night monkeys are nocturnal: they are most active at dawn and dusk. The only exception is Aotus azarae azarae of the Chaco of southern Bolivia, Paraguay and Argentina, which is cathemeral (active during night and day). They are frugivorous; their diet includes fruit, nectar and flower (seasonally important for the A. a. azarae in the Chaco), leaves, and small animals prey such as insects (Wright 1989; Fernandez-Duque 2007).

They are socially monogamous, living in small groups of an adult pair and offspring of different ages (infant, one or two juveniles and sometimes a subadult. In A. a. azarae, a significant number of adults range alone. They 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. Males care for the infants (carry them) (Rotundo et al. 2002, 2005). Lone adults were observed by Villavicencio Galindo (2003) in northern Colombia. Night monkeys are territorial—groups occupy overlapping territories of 5-18 ha (depending on the species and location) (Wright 1978; Fernandez-Duque 2007). Wright (1994) and Fernandez-Duque (2007) review the behaviour and ecology of the genus.

Captive male A. lemurinus reach sexual maturity when 2 years old, and captive female A. vociferans and A. nancymaae first breed when 3-4 years old (Dixson 1983; Fernandez-Duque 2007). In the wild, male A. azarae reach adult weight only when about 4 years old, and age at first reproduction is about 5 years of age (Juárez et al. 2003; Fernandez-Duque 2004). Single offspring are the rule. Wright (1985) recorded births between August and February for A. nigriceps in Peru (Manu National Park), and Aquino et al. (1990) indicated a birth season between December and March for A. nancymaae in north-eastern Peru.

Adult male weight average 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).

Threats [top]

Major Threat(s): No major threats identified. Huiman settlement, deforestation, and hunting are undoubtedly affecting populations, but not to the extent of threatening their continued existence.

Large numbers are used in medical research, sometimes illegally, which should be monitored to understand the effect on populations.

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).

It is listed on Appendix II of CITES.

Citation: Cornejo, F. & Palacios, E. 2008. Aotus nancymaae. The IUCN Red List of Threatened Species 2008: e.T41540A10495465. . Downloaded on 26 April 2017.
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