Learn some Fun Facts About Proboscis Monkeys. The primate world contains some pretty odd specimens, but perhaps none more strange-looking than the Proboscis monkeys. Proboscis means nose, which explains their name, as the noses on the males of this species are clownishly large. These unique monkeys inhabit the island of Borneo in southern Asia and nowhere else on the planet. Their over-sized noses allow the male Proboscis monkeys to make loud bellowing noises to warn of predators or to attract mates. The other notable feature of these monkeys is there protruding stomachs, which allow them to digest their primary food of unripe fruits. Proboscis monkeys can most often be found in the trees of swamps, or sometimes swimming across the rivers of the jungle.