Azara's night monkey (Aotus azarae), also known as the southern night monkey, is a night monkey species from South America. It is found in Argentina, Bolivia, Brazil, Peru and Paraguay. The species is monogamous, with the males providing a large amount of parental care. It is named after Spanish naturalist Félix de Azara. Although primarily nocturnal, some populations of Azara's night monkey are unique among night monkeys in being active both day and night. The species is listed as Least Concern on the IUCN Red List. Taxonomy There are three subspecies of Azara's night monkey. Aotus azarae azarae Bolivian night monkey, Aotus azarae boliviensis Feline night monkey, Aotus azarae infulatus Physical characteristics Due to a lack of data body size and weight measurements of Azara's night monkey have been estimated from a small number of wild samples. The average head and body length of the female is while the male is . The average weight is for male A. a. azarae, for female A. a. azarae, for male A. a. boliviensis, and for female A. a. boliviensis. Its gestation period is about 133 days. The lifespan for Azara's night monkey is unknown, but the captive life span for members of the genus Aotus is believed to be 20 years. Behavior and ecology Azara's night monkey is a monogamous species, with the male remaining present to raise the offspring and provide food. The offspring will only stay with its family until two to three years of age and then will disperse to begin a family of its own. There is very little sexual dimorphism in this species. Azara's night monkey is primarily a frugivore, but also will eat things such as leaves, flowers, and insects. One of the main advantages of being a nocturnal animal is that there is greatly reduced competition from diurnal animals. Azara's night monkey spends its life in trees and becomes more active when the moon is brighter, tending to keep to its well-known paths. However, uniquely among night monkeys, populations of Azara's night monkey from the Gran Chaco are active both day and night. Azara's night monkey can be found sleeping in groups of between 2 and 5 others in trees. The average group size is about 3 monkeys, consisting of an adult pair and their offspring. It leaps from tree to tree but also moves quadrupedally throughout the forest. Habitat and distribution Azara's night monkey