Saving threatened habitats worldwide

Muriqui (Woolly Spider Monkeys)

Staging site



©Neil Burchett

Class: Mammalia

Order: Primates

Family: Atelidae

Scientific Name: Brachyteles hypoxanthus

IUCN Red List status: Critically Endangered

Protected by the following WLT projects:



Species Range (IUCN)


The Muriqui, also known as the Woolly Spider Monkey, is the largest New World primate and has thick, fleecy fur, which is grey or yellow-brown in colour. Two distinct species are recognised; the Northern Muriqui (B. hypoxanthus) which has a black face and the Southern Muriqui (Brachyteles arachnoides) which has a black face mottled with pink.


They have long limbs and prehensile tails, enabling them to be particularly agile amongst the trees. There is a bare patch of skin on the underside of the tip of the tail that acts as a gripping pad to aid their stability and they have evolved hook-like hands, lacking opposable thumbs, for quick and efficient travel between trees; the Northern Muriqui retains only a very short thumb, whilst in Southern Muriquis the thumb is completely absent.


The diet of Muriquis is composed mostly of leaves and fruits, although they also eat flowers, bark and buds. Diet varies throughout the year according to resource availability and it is thought that leaves provide an important food source when fruit availability is low. 

Muriquis live in groups of up to 25 individuals within which multiple related males live together cooperatively. Females tend to give birth to a single offspring in the dry season that runs between May and September.  Once they have reached adolescence at (between the age of five and seven), female offspring will disperse to join other groups whilst males remain within their natal group.


Muriquis are found in highly fragmented patches of Atlantic coastal forest in Brazil. Once an expansive ecosystem, the Brazilian Atlantic coastal forest has been cleared for crops, pastures and human settlement, and is now less than 5% of its original size. Isolated populations survive in fragments of primary and secondary forests. The Northern and Southern species are completely separated from each other.

Threats and Conservation

Following widespread habitat destruction and hunting, Muriquis now survive only in small, isolated populations. The Southern Muriqui has been particularly affected by the devastating effects of habitat destruction; it is critically endangered with fewer than 1,000 individuals remaining. Captive breeding projects are in progress but so far these have had little success.  

Help protect habitat for the Woolly Spider Monkey: Donate to the WLT

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