Golden snub-nosed monkey

Appearance

The adult and subadult golden snub-nosed monkey is sexually dimorphic.

Adult males have large bodies covered with very long, golden guard hairs on their backs and cape area. The crest is medium brown while the back, crown to nape, arms and outer thighs are deep brown. The brown crest also contains physically upright hairs, which the shape are useful for individual identification. Also, when their mouths are open, researchers can observe long canines.

Subadult males have a similar sized body as the fully developed male adult, but have a more slender body. The golden guard hairs on the cape are short and sparse, and their median brown crests show microbanding, while also turning from a brown color.

Adult females are smaller in size and are about half the size of adult males. The dorsum, crow to nape, cape, arms and outer thighs are brown to deep brown in some of the older females. However, golden guard hairs are also present on the back and cape area, but they are shorter in length than in the males. The brown crest shows microbanding. Their breasts and nipples are large and easily visible which is also useful for identification. After pregnancy, it is common to observe infants and newborns hanging beneath the abdomen of females when they are climbing or walking.

Subadult females are smaller than adult females and are about two-thirds the size. The body hair is brown, gradually turning golden but lacking the beautiful golden guard hairs. Their median brown crest also shows microbanding. Their breasts and nipples are also not as large as they are in adult females.

Juveniles are quite small, being less than two-thirds the size of adult females. Their body hair is light brown, gradually turning reddish gold. The rest of their body hair is brown. Golden hairs in the dorsum or cape area are not recognizable nor is the median brown crest present in subadult to adult females and males. Sexual discrimination is difficult because their external genital organs are underdeveloped.

Infants are light brownish gray or light brown, appearing white in sunlight. They are often observed playing with juveniles or other infants, but are noted to spend most of their time beside their mothers or sucking milk. They are also observed clinging from the front of their mothers for protection, feeding, and nurturing. Their sex of the individual cannot be distinguished at this point of time as well as in Newborns.

Newborn babies are dark to light gray. They turn light brownish grey after about 2 months. They are also observed rarely leaving their mothers or other females carrying them, known as alloparenting. Sex at this time is indistinguishable.

Distribution

The distribution range of the golden snub-nosed monkey is limited to the mountains in four provinces in China: Sichuan, Gansu, Shaanxi, and Hubei. This monkey is found at elevations of 1,500-3,400 m. It lives at different elevations and increases or decreases the size of its home range with the change of seasons. The change in home range size and location is dependent upon the availability and distribution of food. The total area covered by its seasonal home ranges is surprisingly large for an arboreal species. One of the largest home ranges found covered 40 km2.

The golden snub-nosed monkey lives in temperate areas. It is limited to broadleaf deciduous, broadleaf deciduous-conifer mixed, or conifer forests.

In a study from 2000-2003 that was conducted in an area surrounding Yuhuangmiao village in Zhouzhi National Nature Reserve, in the Shaanxi Province in China, many methods were used to observe the Sichuan snub-nosed monkeys. The average annual temperature observed over the study period was 6.4°C with a minimum of -8.3°C in January and a maximum of 21.7°C in July. These temperatures observed are blamed for the limited vegetation of the monkeys. The vegetation varies with altitude from deciduous broadleaf forests at low elevations to mixed coniferous broadleaf forests above 2,200 m and coniferous forests above 2,600 m.

Status

The golden snub-nosed monkey is endangered due to habitat loss. For instance, lichens are the main staple of the monkey's diet and dead trees have the greatest lichen coverage. Unfortunately, dead trees are harvested, thus reducing the quality of the habitat and availability of food. The monkey is a highly selective feeder, so damage to its habitat seriously impacts the species.

This primate is found in a number of protected areas, including Baihe Nature Reserve, Foping National Nature Reserve, Shennongjia National Geopark and Wanglang National Nature Reserve. The golden snub-nosed monkey is also listed on Appendix I of the Convention on International Trade in Endangered Species meaning that international trade in this species is prohibited.

Behavior

The golden snub-nosed monkey is found in groups ranging in size from 5-10 individuals to bands of about 600. The social organization of this species can be quite complex. The one-male-units are the basic social unit within groups of golden snub-nosed monkeys with many of the OMUs forming a bigger group. These multi-tier societies consist of several OMUs that include one adult male plus a number of adult females and their offspring. Some observers have even come to conclude that these large foraging groups are multi-male and multi-female societies.


The male may stay solitary, often remaining away from the rest of the group members as they rest. Adult females tend to socialize more with one another than with other males or juveniles. Group members remain close to one another, interactions between different OMUs often result in confrontations. Females of the golden snub-nosed monkey are usually observed to form several close associations with other females. However in conflicts against other units in the surrounding site, both males and females support each other, while also protecting their young .

Protecting the young is a group effort. Mothers often have helpers assisting them with the care of their young. When faced with danger from a predator such as the Northern Goshawk , the young are placed at the center of the group while the stronger adult males go to the scene of the alarm. The rest of the day, the members of the group remain closer to one another with the young protected at the center.

There is little information available on the sleeping cluster patterns of the Sichuan snub-nosed monkeys. However, in a detailed observation of the free-ranging band in the Qinling Mountains in central China, results have suggested that winter night activity of ''Rhinopithecus Roxellana'' is a compromise between antipredator and thermoregulatory strategies and an adaptation to ecological conditions of their temperate habitat. Keeping warm is critical for survival in freezing temperatures, but their thick coats can provide this warmth as well as sleeping in these clusters. Monkeys often sleep in the lower stratum of the tree canopy, avoiding the upper canopy where it is cold and windy. They form larger sleeping clusters at night than in the daytime. The most common types of night-sleeping clusters were adult females and their young, followed by adult females with other adult females. Adult males are usually observed sleeping by themselves or on the lookout for predators or dangers.

There are several hypotheses to explain the formation of sleeping clusters, the most important one being a thermoregulatory process. The thermoregulatory hypothesis suggests that a primary function of sleeping in clusters is the conservation of heat during cold temperatures. Along with thermoregulation, safety from predators is an important principle underlying the formation of sleeping clusters in primates. This antipredation hypothesis suggest that increased cohesion and large sleeping congregations might facilitate predator detection and enhance group defense.

Habitat

The distribution range of the golden snub-nosed monkey is limited to the mountains in four provinces in China: Sichuan, Gansu, Shaanxi, and Hubei. This monkey is found at elevations of 1,500-3,400 m. It lives at different elevations and increases or decreases the size of its home range with the change of seasons. The change in home range size and location is dependent upon the availability and distribution of food. The total area covered by its seasonal home ranges is surprisingly large for an arboreal species. One of the largest home ranges found covered 40 km2.

The golden snub-nosed monkey lives in temperate areas. It is limited to broadleaf deciduous, broadleaf deciduous-conifer mixed, or conifer forests.

In a study from 2000-2003 that was conducted in an area surrounding Yuhuangmiao village in Zhouzhi National Nature Reserve, in the Shaanxi Province in China, many methods were used to observe the Sichuan snub-nosed monkeys. The average annual temperature observed over the study period was 6.4°C with a minimum of -8.3°C in January and a maximum of 21.7°C in July. These temperatures observed are blamed for the limited vegetation of the monkeys. The vegetation varies with altitude from deciduous broadleaf forests at low elevations to mixed coniferous broadleaf forests above 2,200 m and coniferous forests above 2,600 m.

Reproduction

Females are sexually mature at about 5 years old. Males are sexually mature at about 5–7 years old. Mating may occur throughout the year but peaks in the month of October. This approximates gestation at 6–7 months in length. The golden snub-nosed monkey gives birth from March to June....hieroglyph snipped...

In primate research, although male-male competition for mates and female mate choice are the common causes of sexual selection , female-female competition over males is especially important in polygynous species. The Sichuan snub-nosed monkey is a seasonal breeding species of colobine endemic to China, and lives in a multi-level social system. Because the basic social and reproductive unit is the harem or one male unit , which consists of a single resident male, a number of adult females, sub-adult females, juveniles and infants, it has been suggested that sexual competition in this polygynous species is skewed. Females faced with multiple competitors will exhibit a high level of sexual competition, while the single resident male will not experience within-group sexual competition.

Food

The golden snub-nosed monkey eats lichens, young leaves, fruits or seeds, buds, mature leaves, herbs, bark, and flowers. This diet varies from season to season, showing a correlation once again between food availability and home range. This diet also shows a complicated seasonal variation. The monthly diet varies from primarily lichen eater between November and April, to a mixture of folivore and lichen eater from May to July, and to a mixture of frugivore and lichen eater or primarily lichen eater between August and October. For this seasonal variation, the amount of lichens consumed appears to decrease in the summer with the greater availability of fruit or seeds. The monkeys' preferred lichen species seem to be ''Connus controversa'', ''Cerasus discadenia'', ''Salix willichiana'', and ''Malus halliana''. Lichens are found in great profusion on dead trees.

This primate prefers to forage in larger trees of a tree species, and spends most of the time using primary forest and young forest, rarely uses shrub forest and does not use grassland. Even though they primarily forest in the trees and sometimes on the ground, they have certain predators to be aware of. Both mammal predators, such as red dog , wolf , asiatic golden cat , and leopard , and eagle predators, like golden eagle and Northern Goshawk .