Animal Diversity Web

Ge­o­graphic Range

Aotus azarae is found only in South Amer­ica. It in­hab­its the area south from the Rio Madre de Dios and Rio Gua­pore in Bo­livia into Paraguay and north­ern Ar­gentina. In Ar­gentina, the south­ern night owl ranges south of the Rio Bermejo and east from the Rio Paraguai to the Andes. This species is di­vided into two sub­species, Aotus azarae bo­livien­sis and Aotus azarae azarae, by an area ex­tend­ing roughly from Lago Uber­aba on the east to Sucre, Bo­livia, on the west. Aotus a. bo­livien­sis is the north­ern sub­species; A. a. azarae, the south­ern one. Baer (1994), Nowak (1991)

• Biogeographic Regions
• neotropical
  • native

Habi­tat

Aotus azarae live in the trees of Bo­livia, Paraguay, and north­ern Ar­gentina. They sleep there dur­ing the day and rarely come down to the ground. They use lianas to move from tree to tree in the dense for­est. They feed and work at night mak­ing them less apt to deal with pre­da­tion. Grz­imek (1990)

Phys­i­cal De­scrip­tion

Azara's night mon­keys are one of the smaller cebid species. Its head and body length ranges from about 240-370 mm, with a tail length of ap­prox­i­mately 316-400 mm. The tail is not pre­hen­sile and its the pos­te­rior third is black. In a species this small, there is no need for a pre­hen­sile tail be­cause it is so light­weight. There is also no sex­ual di­mor­phism in size or in any other as­pect of the mor­phol­ogy of this species other than the gen­i­talia. The head is rel­a­tively round and the eyes are very large with well-de­vel­oped eye­lids. The retina con­tains rods only. The ears are rather small and can­not be seen be­cause of the short, dense, semi­wooly, and soft fur. The fur has a gray­ish/agouti dor­sum with a slightly more red­dish stripe down the side. The area around the cen­tral face is brown with a white bor­der, and there are large white patches over the eyes. There are also three black stripes that ex­tend into the fore­head red fur on the sides of the neck. Azara's night mon­keys also have a throat sac under the chin that al­lows them to cre­ate res­o­nant vo­cal­iza­tions.

The tooth for­mula is I2/2, C1/1, P3/3, M3/3, and it equals 36 teeth. The upper mo­lars have four cusps, and the lower mo­lars have four or some­times five. This fam­ily is set apart from other pri­mates by their platyrrhine nose (a wide form of the sep­tum that sep­a­rates the nos­trils). The long and thin dig­its bear flat­tened or curved nails. It's great toe is well-de­vel­oped and widely op­pos­able to the other toes. There is no bac­u­lum.

Mac­don­ald (1984), Nowak (1991)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• sexes alike

• Range mass

  0.6 to 1 kg

  1.32 to 2.20 lb

• Range length

  240 to 370 mm

  9.45 to 14.57 in

Re­pro­duc­tion

The fa­ther takes an ac­tive role in rais­ing the young and the re­la­tion­ship among the mother and fa­ther is monog­a­mous. This per­ma­nent pair­ing is based on the in­tol­er­ance of males and fe­males for other in­di­vid­u­als of their own sex.

• Mating System
• monogamous

The ges­ta­tional pe­riod ranges from 126-133 days and usu­ally only 1 baby is born, rarely 2. The weight at birth ranges from 3.2-3.7 ounces. Young are weaned any­where from five to twelve months, and they reach sex­ual ma­tu­rity at two years of age.

Mac­don­ald (1984), Nowak (1990)

• Key Reproductive Features
• iteroparous
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• viviparous

• Range number of offspring

  1 to 2

• Range gestation period

  126 to 133 days

• Range weaning age

  5 to 12 months

• Average age at sexual or reproductive maturity (female)

  2 years

• Average age at sexual or reproductive maturity (male)

  2 years

In the first week of life, the new­born night mon­key nes­tles in his or her mother's groin. Once the sec­ond week comes, the fa­ther as­sists in car­ry­ing the baby at his groin. And by the third week, the fa­ther car­ries the baby there full-time. Be­gin­ning with the sec­ond month, the baby is car­ried in a jockey-like pos­ture on the fa­ther's back, which is where the mon­key will stay until the age of four to five months. Dur­ing the final half of that first year, the young night mon­key in­creases it's play with it's sib­lings. It is also dur­ing this time that the young night mon­key re­lates more to the mother than to the fa­ther.

• Parental Investment
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • male
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • male
    • female
• extended period of juvenile learning

Be­hav­ior

Azara's night mon­keys live as small fam­ily groups, usu­ally con­sist­ing of the par­ents and 2-4 young. Their huge eyes adapt them for noc­tur­nal life. They sleep through the day hud­dled to­gether in hol­low trees or dense fo­liage. They be­come ac­tive at the be­gin­ning of twi­light, by hunt­ing and for­ag­ing through the trop­i­cal forests of South Amer­ica. When they awaken, all fam­ily mem­bers stretch elab­o­rately, uri­nate, and defe­cate. Even­tu­ally one par­ent leaves the sleep­ing tree and makes its way to the first feed­ing tree by way of lianas. The rest of the fam­ily fol­lowed in order, first par­ents then chil­dren. Night mon­keys are most ac­tive when there is a full moon. When there is total dark­ness, they tend to shift some of their ac­tiv­ity into the later and ear­lier hours of day­light. Grz­imek (1990), Nowak (1991)

• Key Behaviors
• arboreal
• nocturnal
• motile
• sedentary
• social

Com­mu­ni­ca­tion and Per­cep­tion

• Perception Channels
• tactile
• chemical

Food Habits

Azara's night mon­keys are om­niv­o­rous, feed­ing on in­sects, fruits, leaves, seeds, bark, flow­ers, gums, bird eggs, and small ver­te­brates. Night mon­keys feed in trees, for­ag­ing at night as a small fam­ily. They tend to feed in the same fruit trees on suc­ces­sive nights. (Mac­don­ald, 1984; Nowak, 1991)

• Primary Diet
• omnivore

• Animal Foods
• birds
• mammals
• amphibians
• reptiles
• eggs
• insects
• terrestrial non-insect arthropods

• Plant Foods
• leaves
• wood, bark, or stems
• seeds, grains, and nuts
• fruit
• flowers
• sap or other plant fluids

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Aotus azarae is of great im­por­tance to hu­mans in that it pro­vides a non­hu­man pri­mate for bio­med­ical re­search. It has played an in­dis­pens­able role in many re­search stud­ies such as the study of malaria and other nat­ural in­fec­tions, viral onco­ge­n­e­sis, oph­thal­mol­ogy re­search, neo­cor­ti­cal or­ga­ni­za­tion and func­tion, and mem­ory-re­lated func­tions. (Baer, 1994)

• Positive Impacts
• research and education

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There are no ad­verse af­fects of Aotus azarae on hu­mans.

Con­ser­va­tion Sta­tus

This species is not yet en­dan­gered. They are very suc­cess­ful due to their noc­tur­nal be­hav­ior. De­spite de­struc­tion of their habi­tat, Aotus azarae have per­sisted be­cause of their abil­ity to adapt to new en­vi­ron­men­tal sit­u­a­tions. These mon­keys are killed for their fur and meat. They are also used ex­ten­sively in bio­med­ical re­search. In­ten­sive de­for­esta­tion has de­creased food sources. (Grz­imek, 1990; Nowak, 1991; Baer, 1994)

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  No special status

Other Com­ments

Their wild pop­u­la­tion has in­creased due to an em­bargo that was im­posed by source con­tries in the 1970's. Be­tween 1968 and 1972, the United States im­ported 20,869 owl mon­keys (in­clud­ing other species of the genus Aotus), pri­mar­ily from Co­lum­bia and Bo­livia. Be­tween 1976 and 1980, the num­ber was dras­ti­cally re­duced to 3300 in­di­vid­u­als. (Baer, 1994)

Con­trib­u­tors

Can­dace T. Smith (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

Baer, J.F., I. Kakoma, R.E. Weller. 1994. Aotus: The Owl Mon­key. Aca­d­e­mic Press, San Diego.

Bri­tan­nica. Bri­tan­nica Search. http://​222.​eb.​com/​cgi-bin/​g?​keywords=durukuli%20%28primate/​

Grz­imek, B. 1990. En­cy­clo­pe­dia of Mam­mals. Mc­Graw-Hill Pub­lish­ing, Co. Vol. 2. pp. 120-173

Mac­don­ald, D.W. 1984. En­cy­clo­pe­dia of Mam­mals. Equinox (Ox­ford) Ltd. pp. 352-352

Nowak, R. M. 1991. Walker's Mam­mals of the World. Fifth Edi­tion. Johns Hop­kins Uni­ver­sity Press, Bal­ti­more. pp. 445-448

Pri­mate Gallery. http://​www.​selu.​com/​~bio/Pri­mate­Gallery/pri­mates/Ce­bidae/Aotinae.​html

Smith­son­ian In­sti­tute. Mam­mals Species of the World. http://​nmnhwww.​si.​edu/​cgi-bin/​wdb/​msw/​names/​query/​1128