Northern Muriqui (Brachyteles hypoxanthus) lives in tropical rainforest across Southeastern Brazil. It feeds on leaves and fruits. Its conservation status is Critically Endangered.
Fascinating facts about the Northern Muriqui
- Northern muriquis stretch up to 4.3 feet (1.3 m) long and tip the scales at 7-10 kg (15-22 lb), making them the largest living New World monkeys. Yet fewer than 1,000 mature individuals survive in the wild, a stark reminder that the biggest New World primates are also the most imperiled. Their sheer size once seemed a guarantee of survival, but now it underscores how urgently their dwindling numbers demand protection.
- Both sexes of northern muriqui grow to the same size, males are no bigger or stronger than females, a trait linked to their unusually egalitarian societies. Males stay in their birth groups while females leave around six years old, before puberty, to join new groups. This sex-balanced size and the cooperative male cliques keep aggression low, offering a rare glimpse of a primate world without dominance hierarchies.
- Their diet swings with the seasons: in the wet months they gorge on high-calorie fruits, while the dry season sees a surge in leaf eating. This flexibility lets them exploit every forest layer, from ground to canopy, and their foraging routes stretch farther when groups grow larger. By swallowing seeds and moving them across the landscape, they act as vital seed-dispersers for countless Atlantic Forest plants.
- Classified as one of the world's most critically endangered primates, the northern muriqui survives in just 12 fragmented populations, with only the Caratinga group deemed viable through the end of the century. To keep a stable population of at least 700 individuals, scientists estimate they need 11,570 ha of continuous forest, a massive area that is rapidly disappearing under logging and development.
- Finding these shy monkeys used to require costly helicopter flights, but in 2017 researchers built the "dronequi," a custom drone with HD thermal cameras. The first model lasted about 10 minutes per battery; the latest can stay aloft for 40 minutes, letting scientists spot, count, and even identify individuals from the sky at a fraction of the cost, dramatically improving monitoring of a species that hides in the canopy.
Sources
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At a glance
RangeSoutheastern Brazil
HabitatTropical rainforest
DietLeaves and fruits
About the Northern Muriqui
In the lush, vibrant canopies of the Brazilian Atlantic Forest, the Northern Muriqui reigns as a gentle giant, its agile form weaving effortlessly through the branches with a quiet confidence that belies its critically endangered status. As it moves, its long, slender limbs unfold like a slow-motion ballet, the soft rustle of leaves and snapping of twigs the only sounds betraying its presence. With a calm, inquisitive gaze, this remarkable primate navigates its dwindling habitat, a poignant reminder of the fragile beauty that hangs in the balance of our planet's ecological destiny.
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