Meet The Owl Monkey: the world’s only nocturnal monkey species

Occasionally, zoologists like to combine the names of animals – something like the parrotfish or the dragonfly. This time they did it for a good reason. Meet the owl monkey, also known as the night monkey, the world’s only nocturnal primate species.

What is an owl monkey and where do they live?

The owl monkeys are a group of 10 species in the genus Aotus, split into two groups. Previously the genus contained only one species with several subspecies, but all have since been elevated to species level; However, there remains some debate about the taxonomy. The two groups are the gray necks, which are found north of the Amazon, and the red necks, which are found south of the Amazon, according to the Wisconsin National Primate Research Center.

All species of owl monkeys live in South America, with the species having different ranges and sometimes occurring in very different tree-based habitats. Azara’s night monkey (Aotus azarae) lives in the Gran Chaco region of South America, according to the New England Primate Conservancy. The Colombian night monkey (Aotus lemurinus) is known by a variety of other common names and is found in the countries of Colombia, Ecuador, and Venezuela.

Three owl monkeys in the trunk of a tree looking outside

Owl monkeys have incredibly close social bonds and have never been found to cheat on their partners.

Image credit: Nowaczyk/

Owl monkeys weigh about 1 kilogram (2.2 pounds) and have thick gray fur over most of their bodies with orange fur over their chest and abdomen, depending on the species. The striking feature of these owl monkeys are their unusually large eyes, which have evolved in response to a nocturnal lifestyle. They are the only New World monkeys that are active at night. The lens of the eyes is more convex than in diurnal monkey species, a chapter on non-human primates in the third edition of Veterinary Medicine Laboratory suggests.

Most species of owl monkey live in pairs or small family groups. “Male and female owl monkeys pair up and form very emotionally strong and lasting relationships. Our research indicates that they are also genetically monogamous, they only reproduce with each other,” said biological anthropologist Professor Eduardo Fernandez-Duque in an interview for Yale News.

Owl monkey fathers are deeply involved in raising the offspring and actively protect their females from other males who mate with them, a 2010 study shows.

‘Owl monkeys are one of the few mammals where we have absolutely no evidence of infidelity; “There is not a single genetic data point that suggests that males and females in mating relationships – sleeping together, eating together, moving together – do not mate exclusively with each other,” Fernandez-Duque continued.

Data for some areas of owl monkey ecology are limited, but it is suggested that the male and female monkeys are similar in size and have a lifespan of about 20 years in captivity, and one observed individual was found to live 11 years in the wild are. .

What does an owl monkey eat?

The gray-handed night monkey (Aotus griseimembra) lives in family groups that forage at night. They eat fruits, flowers, seeds and insects, and will also occasionally eat bird eggs and small birds according to the New England Primate Conservancy.

A note on biomedical research

Owl monkeys have been studied as animal models for use in malaria vaccine research because they are susceptible to the parasite that causes this disease in humans. They have even been used for research and then released back into the wild. Sometimes their nests are destroyed during the trapping process, which could damage owl monkey populations in the long term, the IUCN writes.

“After being subjected to research procedures, the monkeys are released back into the wild without further guidance, potentially causing the movement or hybridization of residents and endangering the transmission of zoonotic risks,” said Angela Maldonado, primatologist and director of Fundación Entropika. , in an interview with Forbes.

Not only are they the best dads in the primate world, helping scientists fight disease and showing us all what a model relationship should look like, but they also have a calling that fits their name.

“They produce relatively loud, low-frequency calls that sound a bit like an owl’s cry, hence the name,” says Fernandez-Duque. This is in contrast to the barred owl, whose call is somewhat similar to that of a monkey.

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