span of the northern muriqui, there are documented individuals reaching past the age of 30 years of age. Conservation and status B. hypoxanthus is one of the world's most critically endangered primates, according to the IUCN Red List of Threatened Species. It is threatened by hunting and (in common with most other primates of the region) destruction and fragmentation of its Atlantic Forest habitat. Among the scattered populations of northern muriqui only one population, living in Caratinga is considered, as of now, viable for the next 100 years. The northern muriqui also suffers from very low genetic diversity and is poorly understood, causing problems in conservation. The estimated wild population of northern muriquis was raised from about 500 to 1000 individuals in 2005, due to new discoveries and research in other forests. Predation Northern muriqui can be preyed upon by ocelots, tayra, and some birds of prey. If a threat or predator is observed, a group of muriqui will vocally call out to warn others Human evolution relevance The northern muriqui has been argued to be important to understanding human evolution, since it is one of the few primates that has tolerant, nonhierarchial relationships among and between males and females, a feature shared with hunter-gatherer humans, but which contrasts with the ranked relationships of most other primates. Group aggression is also rare. The success of males fathering offspring links to the maternal investment they gain from their mothers and coresident female kin. This provides support to the grandmother hypothesis. See also Feliciano Miguel Abdala Private Natural Heritage Reserve, long thought to be the only place where these monkeys still survive References Gallery External links ARKive - images and movies of the Northern muriqui (Brachyteles hypoxanthus) northern muriqui Mammals of Brazil Endemic fauna of Brazil Fauna of the Atlantic Forest Primates of South America Critically endangered animals Critically endangered biota of South America northern muriqui Taxa named by Heinrich Kuhl