The Proboscis Monkey (Nasalis larvatus) is one of the strangest creatures you might see flinging itself amongst the branches in a jungle, and is endemic to the southeast Asian island of Borneo and is found mostly in mangrove forests and on the coastal areas of the island.

It is on the Endangered List too - they have declined at a rate of around 50% or more in the last 40 years, according to the IUCN Red List of Threatened Species, as a result of habitat destruction for logging and oil palm plantations, together with being hunted for food and traditional Chinese medicine. As they are now forced to descend more frequently in search of food, their land predators now include jaguars and some local folk who consider the proboscis monkey a delicacy.

So what’s with the outrageous nose?

The word ‘proboscis’ comes from the Greek word for an elephant's trunk, proboskis, which translates as ‘means for taking food.’ Not to get too technical, but flies and other insects also may have a proboscis, but it's worth knowing that they are not in fact true noses but actually part of their mouths. It may seem hard to believe, but male proboscis monkeys use their fleshy, pendulous noses to attract ‘the girlies’. Scientists think these outsize noses also create an echo chamber that amplifies the monkey's call - a bit like a honk - impressing females and intimidating rival males, and the male will communicate the status of his group with honks, with different ‘honks’ for their offspring or a threat call.

Both sexes give threat calls, but each are different. In addition, females and youngsters will emit ‘female calls’ when angry, and honks, roars and snarls are made during low-intensity fight encounters. Male noses can exceed 10.2 cm in length, and hang lower than their mouths - so size matters to the females, the bigger the better! This large nose may also help with temperature regulation, with the shape allowing for better airflow, which can help cool the blood in the nasal passages before it circulates through the body. Infant offspring have dark blue faces and nearly black fur that signal their young age to other adults, who can assist the mother in caring for it.

The proboscis monkey is quite large; in fact, it is one of the very biggest species in the whole of Asia and is exclusively native to the continent also. There are very few other species of monkeys that can actually match the Proboscis monkey in terms of its size and strength, and despite a weight of up to 50 pounds (including a huge belly), they are surprisingly agile in the forest canopy.

They won’t stray far from a water source, and are capable of swimming up to 20m underwater, being known to swim across rivers. Swimming underwater with partially webbed hands and feet and their eyes open, they search for shellfish, and fruits that have fallen from trees. They are the primate world’s most prolific swimmers, capable of outpacing the crocodiles that are one of their main predators, and have been known to leap into the water with an ungainly belly-flop from heights of over 15m.

Credits: Supplied Image;

Why do proboscis monkeys have so many stomachs?

Here’s something I didn’t know - The proboscis monkey actually has only one stomach, but it is divided into several chambers, similar to that of a cow. These chambers contain bacteria that break down the cellulose in the leaves and plants that are a mainstay of their diet.

Where to see these monkeys

Very few zoos have proboscis monkeys because of their special dietary needs. They are picky eaters, mainly eating leaves from certain plants only, and then only the shoots and young leaves, but they can be found in 16 protected areas in the wild, notably the Labuk Bay Sanctuary in Sandakan, Malaysia, which houses one of the largest isolated population of proboscis monkeys on the Borneo islands.

Author

Marilyn writes regularly for The Portugal News, and has lived in the Algarve for some years. A dog-lover, she has lived in Ireland, UK, Bermuda and the Isle of Man. 

Marilyn Sheridan