Native to the island of Borneo in Southeast Asia, this primate has captured the attention and curiosity of the scientific community and wildlife enthusiasts alike, primarily due to its most distinctive feature: the large, pendulous nose. In adult males, this nose is not only a striking physical characteristic but also a significant aspect of their identity, growing up to 11 cm (4 inches) in length. Females, on the other hand, have much smaller noses, underscoring the sexual dimorphism present within the species. The purpose of this oversized nose has been the subject of much speculation and research, with prevailing theories suggesting it functions as a vocal resonator, amplifying the monkey’s calls throughout the dense, noise-filled mangrove forests and swampy areas they inhabit. Furthermore, the size of the nose is thought to be a signal of virility and social standing among males, potentially playing a crucial role in mate selection.

Beyond their notable noses, Proboscis Monkeys are distinguished by their vibrant fur, which varies from fiery orange to deep brown, and their pronounced potbellies. This unique physique is closely tied to their specialized herbivorous diet, which predominantly consists of leaves, fruits, and the occasional insects. Their digestive system is highly adapted to break down the cellulose found in leaves, a capability that not only dictates their dietary choices but also contributes to their distinct appearance. The potbelly is a direct result of their complex, multi-chambered stomachs necessary for fermenting and digesting the tough plant material.

Proboscis Monkeys are primarily arboreal, spending the majority of their time in the trees. They are also excellent swimmers, with webbed feet that facilitate movement through water, allowing them to traverse the mangrove and swampy environments they call home. This ability to swim is rare among primates and underscores the Proboscis Monkey’s adaptation to its specific habitat.

Distribution

Country

Population est.

Status

Year

Comments

Brunei

2015

Indonesia

<100

Official estimate

EN

2015

Kalimantan

Malaysia

<1,000

Official estimate

EN

2015

Sarawak