Muriqui (Brachyteles arachnoides)

MammalPrimateAtlantic Forest

Overview

The muriqui (genus Brachyteles) is the largest monkey in the Americas — a big, woolly-coated primate of Brazil's Atlantic Forest, sometimes called the “woolly spider monkey” because it combines the dense fur of a woolly monkey with the long limbs and prehensile tail of a spider monkey. The southern muriqui (Brachyteles arachnoides) is shown here. Muriquis hang and swing through the canopy on long arms and a powerful gripping tail.

Muriquis are famous for their unusually peaceful, egalitarian society — they show very little aggression and resolve tensions through tolerance and embracing rather than fighting, which has earned them the nickname “hippie monkeys.”

Conservation note: muriquis are among the most endangered primates on Earth — both species are Critically Endangered, reduced to small populations in fragments of Atlantic Forest. Verify current status at iucnredlist.org.

Habitat & Range

Muriquis live only in the Atlantic Forest of southeastern Brazil — one of the world's most heavily cleared and fragmented biomes. They depend on patches of relatively intact forest with tall trees for feeding and travel, and surviving populations are scattered across isolated reserves and forest remnants.

Diet

Muriquis are folivore–frugivores, eating large amounts of leaves along with fruit, flowers, seeds, and other plant parts; the balance shifts with the seasons. As big plant-eaters ranging through the canopy, they disperse seeds and help shape their forest. They sometimes eat particular plants thought to have medicinal or other effects, a topic of ongoing study.

Behavior

Muriqui society stands out for its peacefulness. Groups are notably tolerant and egalitarian, with little of the dominance fighting seen in many primates; males do not battle aggressively over mates, and tense moments are often defused by embracing one another. They move through the canopy by climbing and by swinging on long arms and a prehensile tail. This gentle, cooperative social style makes them remarkable among monkeys and a favourite example of non-aggressive primate life.

Human Interaction & Conservation

The muriqui is a flagship for the conservation of the Atlantic Forest, one of the most threatened ecosystems anywhere. Centuries of forest clearance and hunting have left both species Critically Endangered, surviving only in fragments. Intensive conservation — protected reserves, monitoring, habitat restoration and connection, and careful management of tiny populations — is working to save them. Consult the IUCN Red List for current status.

More photos of the muriqui