Everyone who has the opportunity to see a Proboscis monkey (Nasalis larvatus) is struck by its giant nose. But there is a second feature which is very typical for Proboscis monkeys and their relatives, the so called Leaf-monkeys - it's their large belly. Indicated by the name of that group of apes, they almost exclusively feed on leaves - and leaves are not easy to digest. Moreover leaves are not very rich in energy-content. So Proboscis monkeys have to eat a lot of leaves and spend most of their time on feeding. In order to obtain enough energy from their meagre nourishment, Proboscis monkeys have got a complicated stomach divided into several parts. Their stomach is quite similar to that of ruminants, which have to face the same problems. Adult Proboscis monkeys are large animals. Males reach a length of about 70 cm and a weight up to 24 kg. Females are significantly smaller, reaching lengths of 60 cm and weights of just 12 kg. The tails of Proboscis monkeys are about as long as their bodies. Their fur is brick-red, the front and the cheeks are of brighter colour and the arms and legs are more greyish. The most obvious feature of Proboscis monkeys is the male's extremely long nose, shaped like a cucumber. Noses of females and young are not small either but don't reach the sizes of the noses of males by far.