Northern Muriqui, Brachyteles hypoxanthus

The Northern Muriqui (Brachyteles hypoxanthus) is an endangered muriqui, meaning woolly spider monkey, species that is endemic to Brazil. It is rare among primates in that it shows egaliterian social relationships. It can be found in the Atlantic forest region of the Brazilian states of Espirito Santo, Minas Gerais, Bahia, and Rio de Janeiro. Muriquis are the biggest species of New World monkeys. The northern muriqui can grow up to 4.3 feet tall. This species feeds mostly on leaves and twigs, but it will also consume fruit. It frequently hangs upside-down by its prehensile tail while it is eating.

Northern muriquis can be individually recognized by their natural markings and their facial features, such as the color of their fur and the patterning, ear shape, face shape, and pigmentation. Their sex can normally be determined within a week or so of being born based on the shape and the positioning of their genitals. The structures for the Northern Muriqui’s are groups of the males and groups of the females. Female Muriqui’s are more independent than the males. The female Muriqui also engage in sex with more than one partner. A fact to note about the male Muriqui is that there is almost no interaction between the male the offspring. On the brief occasion that there is an interaction between these two, the infants would be the one to initiate.

This species is one of the world’s critically endangered primates. The species is listed as Critically Endangered on the IUCN Red List of Threatened Species. It is threatened by hunting, destruction, and fragmentation of its Atlantic Forest habitat. Among the scattered populations of these monkeys only one population, living in Caratinga is considered, currently, viable for the next 100 years. The estimated wild population or northern muriquis has increased from roughly 500 to 1,000 individuals in 2005, because of new discoveries and research in other forests.

Image Caption: Northern Muriqui (Brachyteles hypoxanthus). Credit: Peter Schoen/Wikipedia (CC BY-SA 2.0)