Owl or Night Monkey

Species: Aotus trivirgatus.

PHYSICAL DESCRIPTION: Male Ht. 1.3 ft., Wt. 2 lbs. Female Ht. 1.3 ft., Wt. 2 lbs. Coat: grizzled brown, gray, or reddish on back, back of head, and limbs; underside buff-white to bright orange; distinctive striping on heads. Large eyes. Variable chromosome number. Quadrupedal: climbing, springing, and branch running. Longevity: about 12 years in wild.

GEOGRAPHIC LOCATION: Central and South America.

ECOLOGY: Nocturnal arboreal forager. Adaptable to a variety of environments; dry and rain forest. Home range: 1 km2 Day range: .7 km.

DIET: fruit (55%), leaves (25%), insects (15%), prey and gum (5%).

SOCIAL ORGANIZATION: Monogamous family groups, Adult pair + juveniles and infants. Exclusive territories, but active defense only of fruiting trees. Male transfer at about 3 yrs. Females may remain near their parents' territory.

REPRODUCTION: Males sexually mature at 5 yrs. Females sexually mature at 4 yrs. Gestation length: 5 months. No estrus swellings. Litter size: 1. Interbirth interval: 1 yrs. Infant birth wt.: .4 lbs.

PARENTAL CARE: Infants carried by males for 4 mo., transferred to females for nursing. Males also share food, groom, and play with offspring. Siblings carry infants. Weaning at .5 yr.

TOPIC OF SPECIAL INTEREST: Nocturnality. Extensive paternal and sibling care of infants.


Terborgh, J. 1983. Five new world primates. Princeton: Princeton University Press.

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