Maroon Leaf Monkey (Presbytis rubicunda) lives in tropical rainforest across Southeast Asia. It feeds on leaves and fruits. Its conservation status is Vulnerable.
Fascinating facts about the Maroon Leaf Monkey
- Maroon leaf monkeys exist only on Borneo and the tiny neighbouring Karimata island, making them true island endemics. They are confined to the dense dipterocarp evergreen forest that blankets the island, a habitat that provides the continuous canopy they need. The species primarily inhabits forests below 2,000 m altitude, where the trees are tall and continuous.
- To supplement minerals they deliberately eat the acidic topsoil of termite mounds. This behaviour is observed in April, June and August, when the monkeys collect soil rich in calcium, magnesium, potassium and phosphorus. The termite mound soil is unusually acidic and contains high levels of exchangeable cations, a condition linked to the termites' saliva. By ingesting this mineral-rich material they obtain essential nutrients that are scarce in their leafy diet.
- A 25-month study showed their feeding is dominated by young leaves, making up 46 percent of their feeding time. Seeds account for 38 percent, whole fruits 12 percent, while bark, pith and flowers together contribute the remaining few percent. When fruit and seed abundance rises, the monkeys shift to spending more time on those resources, but they still rely heavily on young leaves as a fallback.
- Maroon leaf monkeys occupy unusually large home ranges and are found at low population densities compared with most primates. This pattern is thought to stem from their reliance on specific tree species that are both rare and widely scattered across the forest. As arboreal primates they spend the majority of their lives high in the canopy of Borneo's dipterocarp evergreen forest, moving over extensive areas to locate these scarce resources.
- When fruit is abundant, maroon leaf monkeys dramatically increase their intake of seeds and whole fruits. The fruiting peak runs from June to September, during which the forest produces a surge of fruit that the monkeys exploit heavily. In these periods they devote the bulk of their feeding time to the plentiful seeds and fruits, shifting away from their usual reliance on young leaves.
Sources
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At a glance
RangeSoutheast Asia
HabitatTropical rainforest
DietLeaves and fruits
About the Maroon Leaf Monkey
In the lush, emerald canopies of Borneo's rainforests, the maroon leaf monkey navigates with effortless agility, its slender fingers and toes grasping for branches as it leaps from tree to tree with a soft, whooshing sound. With eyes like dark, shining pools, this enigmatic creature surveys its surroundings, its rust-hued fur blending seamlessly into the dappled light filtering through the leaves. As it moves, the maroon leaf monkey embodies a quiet, unassuming elegance, its very existence a testament to the beauty and fragility of the forest ecosystem it calls home.
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