Aotus lemurinuslemurine night monkey

Geographic Range

Aotus lemurinus , commonly known as the owl monkey or night monkey, is found in Central and South America. They occur from Panama to northeastern Argentina, and from Peru and Equador to Guyana and Brazil.


Owl monkeys occupy a variety of habitats. They are found from moist rainforest to dry scrub. Aotus lemurinus is most common in dense forest, where many vines are present. They can be found in all levels of the forest but are rarely found on the ground.

Physical Description

Aotus lemurinus can be recognized by its small rounded head and owl-like face. Their brown eyes are large and round. Their thick white eyebrows lie below three black stripes on their head. A large black spot is found between their eyes. The eyeshine from these nocturnal monkeys is a bright reddish orange. Fur is dense and wooly and is usually grey in color. The color of the underparts of the monkey ranges from a pale yellow to a bright orange. Their tail is non-prehensile and mostly black, but may have brown or dark orange coloring on it. The tail always has a black tip. Their fingers are long and slender, with expanded pads on the tips. This monkey exhibits no sexual dimorphism. Weight ranges from 0.5 to 1.3 kg.

  • Range mass
    0.5 to 1.3 kg
    1.10 to 2.86 lb
  • Average mass
    0.0009 kg
    0.00 lb


Aotus lemurinus is a monogamous mammal.

Aotus lemurinus reaches sexual maturity at approximately 2.5 years of age. Females have an ovarian cycle which ranges from 13 to 19 days. There is no external indication of estrous. Males initiate reproduction. Reciprocal grooming has been observed in this species only prior to mating. Gestation period is 133 days. Females give birth to single young or sometimes twins.

  • Range number of offspring
    1 to 2
  • Average number of offspring
  • Average gestation period
    133 days
  • Average gestation period
    135 days
  • Average age at sexual or reproductive maturity (female)
    2.5 years
  • Average age at sexual or reproductive maturity (male)
    2.5 years

The male and female both care for the young.

  • Parental Investment
  • precocial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • male
      • female


  • Range lifespan
    Status: captivity
    33.8 (high) years


Aotus lemurinus is nocturnal and is most active several hours after dusk and before dawn. These monkeys live in small family groups consisting of between 2 to 5 members, including the adult pair and their offspring. During the day family groups will sleep either in tree hollows, vine covered trees, or dense brush. They are monogamous, and both parents play a role in raising their young. These monkeys are vocal and have various calls ranging from soft and low pitched grunts and clicks to louder, owl - like hoots. When danger is sensed they will produce a high - pitched shriek as an alarm signal. They are fairly sedentary.

Communication and Perception

Food Habits

Aotus lemurinus feeds at night, where they typically feed in the canopy. Their diet is broad, including fruit, flower nectar, foliage, and insects. These monkeys have also been known to feed on small birds and mammals.

  • Animal Foods
  • birds
  • mammals
  • insects
  • Plant Foods
  • leaves
  • fruit
  • nectar

Economic Importance for Humans: Positive

Aotus lemurinus is commonly used in biomedical research.

Conservation Status

Aotus lemurinus populations have suffered due to collection for biomedical research and some hunting.


Sarah Soderman (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.



living in the southern part of the New World. In other words, Central and South America.

World Map


Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


uses smells or other chemicals to communicate


animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.


forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.


offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).


Having one mate at a time.


having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.


active during the night


an animal that mainly eats all kinds of things, including plants and animals


rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

scrub forest

scrub forests develop in areas that experience dry seasons.


remains in the same area


reproduction that includes combining the genetic contribution of two individuals, a male and a female


associates with others of its species; forms social groups.


uses touch to communicate


reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

young precocial

young are relatively well-developed when born


"Aotus, the Owl Monkey" (On-line). Accessed November 15, 1999 at

Boitani, L., S. Boitani. 1983. Simon and Schuster's Guide to Mammals. New York: Simon and Schuster.

Emmons, L., F. Feer. 1990. Neotropical Rainforest Mammals. Chicago: The University of Chicago Press.

Reid, F. 1997. A Field Guide to the Mammals of Central America and Southeast Mexico. New York: Oxford University Press.