The proboscis monkey has one of the most unusual appearances of any of the leaf-eating monkeys of the family Cercopithecidae. Both the Latin and common names of this species refer to the mature males' large pendulous nose that hangs down over their mouth (4). Local people referred to these large monkeys with their potbellies and red noses as 'Dutch monkeys' as they were considered such a caricature of the Dutch sailors and plantation owners of the area (4). Apart from their large noses, male proboscis monkeys are also distinctive by being much larger and heavier than females, and having a bright red, visible penis and black scrotum (2) (5). The coat is a light brown with red on both the crown of the head and the shoulders; the limbs and tail are grey in colour and there are cream patches on the throat (5). Infants are born with black fur and a vivid blue face (4). The cause of the males' large nose is still a matter of contention but may be a form of sexual selection, with females preferring males with large noses possibly as these enhance their vocalisations (4).