Nosach

The most striking sign of a nosal is its large nose, similar to a cucumber, which, however, is only present in males. The nose coat on the upper side is yellowish brown, on the lower side it is painted white. The arms, legs and tail are gray, and the hairless face is red. The size of the noses reaches from 66 to 75 cm, the tail is about as long as the body. The mass of males ranges from 16 to 22 kg, - twice as much as the mass of females.

Nosachi live in forests and are active in the daytime. They spend the night and morning on vacation, and the peak of their activity occurs in the afternoon or evening .

Nosachi live in rainforests or mangroves and never move far away from the water. They are excellent swimmers, jumping into the water directly from the trees and able to overcome up to 20 meters, moving under water. Of all primates, they are perhaps the best swimmers. Within the open shallow water of the mangroves, they move on four limbs, but they overcome the distance between the densely growing mangrove trees on two legs, walking almost vertically. Along with gibbons and humans, they are thus the only primates who can overcome relatively long distances directly on two legs.

Nosach live in groups of 10 to 30 individuals, which can be either harem groups (one male and many females), or purely male groups. The males leave the group in which they were born upon reaching puberty, and the females remain in it. However, sometimes it happens that adult females leave their male and adjoin another. In search of food or for a night's rest, often several groups are combined into one large group.

The appointment of large noses in males is unknown. Perhaps it serves for sexual attractiveness - the larger the nose, the more chances to impress and win the female. According to another version, the size of the nose determines the status of the male in the group - males with large noses occupy a higher position among relatives. Igor Akimushkin suggested that a large nose allows males to make louder sounds ^{[2] [3]} .

Nose food mainly consists of leaves and fruits . In small volumes, they feed on plant flowers .

The mating initiative comes from a female who sticks out her lips, shakes her head from side to side and shows the male her genitals. About 170 days after mating, one cub is usually born, which, unlike adults, has a blue face. Mother feeds him milk for seven months, but after that she remains in close contact with him for some time. Puberty occurs between the ages of five and seven years, in males later than in females.

Deforestation is currently a major threat to the nosy. This species also suffers from hunting, although it is protected by law. According to IUCN , nosoci are at risk of extinction.

• Ronald M. Nowak: Walker's Mammals of the World. Johns Hopkins University Press, 1999 ISBN 0-8018-5789-9