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Aotus nigriceps

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA MAMMALIA PRIMATES AOTIDAE

Scientific Name: Aotus nigriceps
Species Authority: Dollman, 1909
Common Name(s):
English Black-headed Night Monkey, Peruvian Night Monkey
Spanish Cuatro Ojos, Macaco Da Noite, Mono Nocturno, Quatro Ojos
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)
Justification:
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. However, given ongoing development projects, the species does require close population monitoring.
History:
2003 Least Concern (IUCN 2003)
2003 Least Concern

Geographic Range [top]

Range Description: Aotus nigriceps occurs throughout a large part of the central and upper Amazon, south of the mainstream and along the right bank of the Rio Jutaí in the west. In the east, it extends to the rios Tapajós and Juruena (Aotus azarae infulatus occurs to the east of the rios Tapajós and Juruena). It occurs throughout the state of Rondônia in Brazil, restricted to east of the Rio Guaporé. In Bolivia, it occurs north of the Río Madre de Dios in the Department of Pando (Hershkovitz 1983; Brown and Rumiz 1986; Anderson 1997), extending to the south-eastern and central Peruvian Amazon, west through the Río Ucayali basin to the east (right bank) of the Rio Huallaga (A. miconax coccurs to the west) to about 7ºS (Aquino and Encarnación 1994a).
Countries:
Native:
Bolivia, Plurinational States of; Brazil (Acre, Amazonas, Mato Grosso, Pará, Rondônia); Peru
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Wright (1981, 1985) estimated a density of 36-40 indviduals/km² at Cocha Cashu, Manu National Park. Aquino and Encarnación (1994b) reviewed population structure and densities for the genus.
Population Trend: Unknown

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, 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). In Cocha Cashu, Manu National Park, Peru, Wright (1989) recorded home range size for A. nigriceps of 7 to 14 ha. 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.

Size:
Adult male weight 875 kg (n=1), adult female weight 1.04 kg (n=2) (Peres 1993a).
Systems: Terrestrial

Threats [top]

Major Threat(s): A wide ranging species of the upper Amazon, there are currently no major threats believed to be resulting in a significant population decline. However, populations have been depleted over large areas in the states of Acre and Rondônoia, and with infrastructure development along major development corridors ((Porto Velho - Cuiabá and Porto Velho- Manausm and the Rio Madeira itself), it is likely that large tracts of forest will be lost in the future.

Conservation Actions [top]

Conservation Actions: Confirmed, or may occur, in several protected areas, including:

Bolivia
Manuripe National Reserve (Brown and Rumiz 1986)

Brazil
Amazonia National Park (1,114,917 ha) (in range)
Serra do Divisor National Park (846,408 ha)
Juruena National Park
Pacáas Novos National Park
Abufari Biological Reserve (224,819 ha)
Guaporé Biological Reserve (618,173 ha)
Rio Acre Ecological Station (79,418 ha)

Peru
Manu National Park (1,532,806 ha) (Wright 1978, 1985).

It is listed on Appendix II of CITES.

Citation: Cornejo, F. & Palacios, E. 2008. Aotus nigriceps. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 01 September 2014.
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