Night monkey

(Aotidae)

Class: Mammalia

Order: Primates

Family: Aotidae

Thumbnail description
Gracile monkeys with a slender body and a rounded head; face flat with short muzzle; nocturnal habits reflected by remarkably large eyes, resulting in the alternate name "owl monkeys," and inconspicuous pelage coloration

Size
Medium-sized monkeys weighing approximately 2 lb (910 g)

Number of genera, species
1 genus; 8 species

Habitat
Evergreen tropical rainforest, gallery forest, and mixed deciduous forest

Conservation status
Vulnerable: 2 species; Data Deficient 1 species

Distribution
After howler monkeys (genus Alouatta), this is the second most widely distributed genus among the New World monkeys, occurring over a vast range including Panama and a large part of South America

Evolution and systematics

Traditionally, only a single night monkey species (Aotus trivirgatus) was recognized, but chromosomal evidence revealed considerable diversity. This is hardly surprising, given the extensive geographical range covered by Aotus. It is now widely accepted that there are between five and nine night monkey species, and eight species can be recognized as a basic minimum. Night monkeys provide a graphic example of a persistent failure to recognize cryptic species among nocturnal primates, because they differ relatively little in visually obvious characters. Molecular evidence indicates that some individual night monkey species diverged at a very early stage and also suggests that there is no close relationship between the night monkey lineage and any other group of New World monkeys. It is hence appropriate to recognize a separate family Aotidae for the night monkeys, rather than just a subfamily (Aotinae). It has been customary to include the titi monkeys (genus Callicebus) with the night monkeys in the subfamily Aotinae, but molecular evidence does not indicate any phylogenetic association between Aotus and Callicebus, so there is no justification for classifying these two genera together.

The night monkeys can be divided into a gray-neck group of four species occurring essentially north of the River Amazon (Aotus hershkovitzi, Aotus lemurinus, Aotus trivirgatus and Aotus vociferans) and a red-necked group of four species occurring almost exclusively south of the Amazon (Aotus azarai, Aotus miconax, Aotus nancymaae and Aotus nigriceps).

As is the case for New World monkeys, generally, there is very little fossil evidence to document the evolution of night monkeys. However, some fragmentary remains from the early Miocene of the La Venta site in Colombia have been allocated to a species in the modern genus Aotus (Aotus dindinensis). The lower jaw and teeth closely resemble those of the modern night monkey and a fragment of the skull indicates that large eyes were present, suggesting that nocturnal habits were already present as in living species.

Physical characteristics

The body is slender and covered with dense fine hair, varying in color from gray to brown dorsally and from yellow to orange ventrally. Conspicuous white or pale gray patches surround the eyes and the mouth, and the white areas above the eyes are emphasized to varying extents by three spurs of dark fur in the midline and on either side of the crown. The head is rounded and the muzzle does not protrude. The tail, which is not prehensile, is typically longer than the body and densely furred. Average head and body length is 13.5 in (34 cm); average tail length is 15 in (37 cm). There is no sexual dimorphism in size and the average body mass for both sexes is approximately 2 lb (910 g).

Distribution

Widely distributed in Central and South America, from the foothills of the Andes eastward. Occurs in Panama, Nicaragua, Colombia, Peru, Bolivia, Brazil, Venezuela, and Paraguay.

Habitat

Wide distribution throughout evergreen tropical rainforests and certain dry forest areas, between sea level and 10,700 ft (3,200 m).

Behavior

Uniquely among higher primates, night monkeys are typically nocturnal, although cathemeral activity (mixed day and night activity) has been reported for some populations. Several lines of evidence indicate that they have become secondarily adapted for nocturnal life, following divergence from a diurnal ancestor. During the daytime, they typically sleep in tree hollows. Their basal metabolism is relatively low and this is reflected in quite sluggish movement and limited ranging during the nocturnal phase of activity. Olfactory marking is performed with urine and with marking glands. There is a small marking gland on the chest and a diffuse glandular area on the underside of the tail base. Night monkeys also perform "urine washing," in which the palms of the hands and the soles of the feet are impregnated with urine that is then deposited during locomotion.

Feeding ecology and diet

Primarily consume fruits, with a supplement of arthropods (mainly insects) and perhaps small vertebrates and eggs.

Reproductive biology

Field studies have consistently indicated that night monkeys are monogamous, living in pairs along with any immature offspring. The testes are relatively small and spermatogenesis seems to take place with a remarkably low turnover. For Aotus lemurinus griseimembra, the ovarian cycle is 15–16 days long and the gestation period was found to be 133 days from a single timed mating. The latter figure is likely to apply to all night monkeys, as an overall range of gestation periods of 122–141 days has been reported for a captive colony containing Aotus azarai, A. lemurinus, A. nancymaae, and A. vociferans. Single births are typical. The infant is carried clinging to an adult's fur, and both parents participate in infant carriage.

Conservation status

Two species are listed as Vulnerable (Aotus lemurinus, A. miconax); one species is Data Deficient (A. hershkovitzi).

Significance to humans

Because of their nocturnal habits, night monkeys are relatively protected from human interference, but they may occasionally be hunted for food. Several night monkey species have been used in medical research, notably because they can be infected with human malaria.

Species accounts

Resources

Baer, Janet F., Richard E. Weller, and Ibulaimu Kakoma, eds. Aotus: The Owl Monkey. San Diego: Academic Press, 1994.

Dixson, Alan F. "The Owl Monkey (Aotus trivirgatus)." In Reproduction in New World Primates, edited by John P. Hearn. Lancaster: MTP Press, 1982.

Dixson, Alan F., Rosemary C. Bonney, Dirk Fleming, and Robert D. Martin. "Reproductive Biology of the Owl Monkey Aotus trivirgatus griseimembra." In Non-Human Primate Models in Human Reproduction, edited by T. C. Anand Kumar. Basel: Karger, 1980, pp. 61–68.

Groves, Colin P. Primate Taxonomy. Washington, DC: Smithsonian Institute Press, 2001.

Napier, Prudence H. Catalogue of Primates in the British Museum (Natural History) and Elsewhere in the British Isles. Part I: Families Callitrichidae and Cebidae. London: British Museum (Natural History), 1976.

Wright, Patricia C. "The Night Monkeys, Genus Aotus." In Ecology and Behavior of Neotropical Primates, Vol. 1, edited by Adelmar F. Coimbra-Filho and Russell A. Mittermeier. Rio de Janeiro: Academia Brasileira de Ciências, 1981, pp. 211–240.

Aquino, R., and F. Encarnacion. "Population densities and geographic distribution of night monkeys (Aotus nancymai and Aotus vociferans) (Cebidae, Primates) in northeastern Peru." American Journal of Primatology 14 (1988): 375–381.

Ashley, M. V., and J. L. Vaughn. "Owl monkeys (Aotus) are highly divergent in mitochondrial cytochrome c oxidase (COII) sequences." International Journal of Primatology 16 (1995): 793–806.

Canavez, F. C., M. M. Moreiera, J. J. Ladasky, A. Pissinati, P. Parham, and H. Seuánez. "Molecular phylogeny of New World primates (Platyrrhini) based on beta2-microglobin DNA sequences." Molecular Phylogenetics and Evolution 12 (1999): 74–82.

Dixson, A. F., and D. Fleming. "Parental behaviour and infant development in owl monkeys (Aotus trivirgatus griseimembra)." Journal of Zoology, London 194 (1981): 25–39.

Galbreath, G. J. "Karyotypic evolution in Aotus." American Journal of Primatology 4 (1983): 245–251.

Gozalo, A., and E. Montoya. "Reproduction of the owl monkey (Aotus nancymai) (Primates: Cebidae) in captivity." American Journal of Primatology 21 (1990): 61–68.

Hershkovitz, Phillip. "Two new species of night monkeys, genus Aotus (Cebidae, Platyrrhini): A preliminary report on Aotus taxonomy." American Journal of Primatology 4 (1983): 209–243.

Horovitz, I., R. Zardoya, and A. Meyer. "Platyrrhine systematics: A simultaneous analysis of molecular and morphological data." American Journal of Physical Anthropology 106 (1998): 261–281.

Hunter, J. M., R. D. Dixson, F. Alan, and B. C. C. Rudder. "Gestation and inter-birth intervals in the owl monkey (Aotus trivirgatus griseimembra)." Folia Primatology 31 (1979): 165–175.

Le Maho, Y., M. Goffart, A. Rochas, H. Felbabel, and J. Chatonnet. "Thermoregulation in the only nocturnal simian: the night monkey Aotus trivirgatus." American Journal of Physiology 240 (1981) R156–R165.

Ma, N. S. F., R. N. Rossan, S. T. Kelley, J. S. Harper, M. T. Bedard, and T. C. Jones. "Banding patterns of the chromosomes of two new karyotypes of the owl monkey, Aotus, captured in Panama." Journal of Medical Primatology 7 (1978): 146–155.

Malaga, C. A., R. E. Weller, R. L. Buschbom, J. F. Baer, and B. B. Kimsey. "Reproduction of the owl monkey (Aotus sp.) in captivity." Journal of Medical Primatology 26 (1997): 147–152.

Martin, R. D. "Long night for owl monkeys." Nature 326 (1987): 639–640.

Setoguchi, T., and A. L. Rosenberger. "A fossil owl monkey from La Venta, Colombia." Nature 326 (1987): 692–694.

Smith, R. J., and W. L. Jungers. "Body mass in comparative primatology." Journal of Human Evolution 32 (1997): 523–559.

Torres, O. M., S. Enciso, F. Ruiz, E. Silva, and I. Yunis. "Chromosome diversity of the genus Aotus from Colombia." American Journal of Primatology 44 (1998): 255–275.

Wright, P. C. "Home range, activity pattern and agonistic encounters of a group of night monkeys (Aotus trivirgatus) in Peru." Folia Primatology 29 (1978): 43–55.

[Article by: Robert D. Martin, PhD]

Soft, curly-haired, nocturnal monkey; red to gray-brown with a long, nonprehensile tail. Good house pets. Called also douroucouli, owl monkey, Aotus spp.

Night monkeys[1]
A night monkey in Panama
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Primates
Suborder:	Haplorrhini
Infraorder:	Simiiformes
Parvorder:	Platyrrhini
Family:	Aotidae Poche, 1908 (1865)
Genus:	Aotus Illiger, 1811
Type species
Simia trivirgata Humboldt, 1811
Species
see text

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). They are widely distributed in the forests of Central and South America, from Panama south to Paraguay and northern Argentina. The species that live at higher elevations tend to have thicker fur than the monkeys at sea level. The genus name means "earless"; they have ears, of course, but the external ears are tiny and hard to see. Night monkeys have big brown eyes and therefore have increased ability to be active at night. They are called night monkeys because 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).^[2] Both male and female Night Monkeys weigh almost the same amount. For example, in one of these Night Monkeys, A. azarae, the male weighs 2.76 pounds while the female weighs 2.75 pounds.

Night monkeys make a notably wide variety of vocal sounds, with up to eight categories of distinct calls (gruff grunts, resonant grunts, screams, low trills, moans, gulps, sneeze grunts and hoots), and a frequency range of 190-1,950 Hz.^[3] 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.^[4]

All night monkeys form pair bonds, and live in family groups of the mated pair with their immature offspring. Family groups defend territories by vocal calls and scent marking. 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.

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 models in malaria research.^[5]

Contents 1 Taxonomy 2 Classification 3 References 4 External links

Taxonomy

Until 1983, all night monkeys were placed into only one (A. lemurimus) or two species (A. lemurinus and A. azarae). Some authors still believe that there are only two or three true species, the remaining taxa being subspecies of these. An often used distinction is an even split of eight species between 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).^[1] It has been argued that the taxa otherwise considered subspecies of A. lemurinus – brumbacki, griseimembra and zonalis – actually should be considered separate species,^[6][7] whereas it has been argued that A. hershkovitzi is a junior synonym of A. (l) lemurinus.^[6] 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,^[8] an essential part of the argument for recognizing this new species was differences in the chromosomes.^[7] 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.^[9] Fossil species have (correctly or incorrectly) been assigned to this genus, but only extant species are listed below.

Classification

• Family Aotidae
  • Aotus lemurinus (gray-necked) group:
    • Gray-bellied Night Monkey, Aotus lemurinus.
    • Panamanian Night Monkey, Aotus zonalis.
    • Hernández-Camacho's Night Monkey, Aotus jorgehernandezi.
    • Gray-handed Night Monkey, Aotus griseimembra.
    • Hershkovitz's Night Monkey, Aotus hershkovitzi – probably a synonym of A. lemurinus.^[6]
    • Brumback's Night Monkey, Aotus brumbacki.
    • Three-striped Night Monkey, Aotus trivirgatus.
    • Spix's Night Monkey, Aotus vociferans.
  • Aotus azarae (red-necked) group:
    • Azara's Night Monkey, Aotus azarae.
    • Peruvian Night Monkey, Aotus miconax.
    • Nancy Ma's Night Monkey, Aotus nancymaae .
    • Black-headed Night Monkey, Aotus nigriceps.

References

1. ^ ^{a b} Groves, C. (2005). Wilson, D. E., & Reeder, D. M.. ed. Mammal Species of the World (3rd ed.). Johns Hopkins University Press. pp. 139-141. ISBN 0-801-88221-4. http://www.bucknell.edu/msw3. 
2. ^ Owl monkey. Primate info net.
3. ^ Moynihan, M. (1964). "Some behavior patterns of platyrrhine monkeys. I. The night monkey (Aotus trivirgatus)". Smithsonian Miscellaneous Collections 146 (5): 1–84. 
4. ^ Jacobs, G. H., Deegan, J. F., Neitz, J., Crognale, M. A. (1993). "Photopigments and colour vision in the nocturnal monkey, Aotus". Vision Research 33: 1773–1783. doi:10.1016/0042-6989(93)90168-V. 
5. ^ Baer, J.F., Weller, R.E. and Kakoma, I. (eds), ed (1994). Aotus : The Owl Monkey. San Diego: Academic Press. ISBN 0-12-072405-7. 
6. ^ ^{a b c} Defler, T.R., Bueno, M. L., & Hernández-Camacho, J. I. (2001). The taxonomic status of Aotus hershkovitzi: Its relationship to Aotus lemurinus lemurinus. Neotropical Primates 9(2): 37-52.
7. ^ ^{a b} Defler, T. R., & Bueno, M. L. (2007). Aotus Diversity and the Species Problem. Primate Conservation 2007 (22): 55–70.
8. ^ Torres, O. M., Enciso, S., Ruiz, F., Silva, E., & Yunis, I. (1998). Chromosome diversity of the genus Aotus from Colombia. American Journal of Primatology 44(4): 255–275.
9. ^ Pieczarka, J. C., de Souza Barros, R. M., de Faria Jr, F. M., Nagamachi, C. Y. (1993). Aotus from the southwestern Amazon region is geographically and chromosomally intermediate between A. azarae boliviensis and A. infulatus. Primates 34: 197-204.

External links

Wikispecies has information related to: Aotidae

Wikispecies has information related to: Aotus

• Primate Info Net Aotus Factsheet

v • d • e Extant primate families by suborder Kingdom Animalia · Phylum Chordata · Class Mammalia · Infraclass Eutheria · Superorder Euarchontoglires Strepsirrhini Cheirogaleidae · Lemuridae · Lepilemuridae · Indriidae · Daubentoniidae · Lorisidae · Galagidae Haplorrhini Tarsiidae · Cebidae · Aotidae · Pitheciidae · Atelidae · Cercopithecidae · Hylobatidae · Hominidae

v • d • e Extant species of family Aotidae Kingdom: Animalia · Phylum: Chordata · Class: Mammalia · Order: Primates · Suborder: Haplorrhini Aotus (Night monkeys) Gray-neck group: Gray-bellied Night Monkey (A. lemurinus) · Hershkovitz's Night Monkey (A. hershkovitzi) · Brumback's Night Monkey (A. brumbacki) · Three-striped Night Monkey (A. trivirgatus) · Spix's Night Monkey (A. vociferans) · Hernández-Camacho's Night Monkey (A. jorgehernandezi) Red-neck group: Peruvian Night Monkey (A. miconax) · Nancy Ma's Night Monkey (A. nancymaae) · Azara's Night Monkey (A. azarae) · Black-headed Night Monkey (A. nigriceps) Category

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)