Quick answer
Key facts about proboscis monkey — size, diet, habitat, and conservation in one place.
The big nose
Male noses amplify honking calls and may signal mate quality to females. Larger noses correlate with higher rank and reproductive success in harem groups.
Swimming ability
Webbed feet and partial webbing between fingers help proboscis monkeys cross rivers to escape predators and reach feeding trees. Crocodiles remain a real threat.
Leaf digestion
Pot bellies house fermenting bacteria that break down toxic unripe fruit and fibrous leaves — a specialised folivore among colobines.
Endangered endemism
Oil palm expansion destroys riverine forest — proboscis monkeys cannot survive in oil palm monoculture. Sukau and Kinabatangan river cruises support ecotourism conservation.