BLACK SNUB-NOSED MONKEY: CHARACTERISTICS, BEHAVIOUR, MATING

BLACK SNUB-NOSED MONKEY

black snub-nosed monkey

Black snub-nosed monkeys (Rhinopithecus bieti) are found only in China — mainly in northwest Yunnan, southeast Tibet and in Guizhou. They live in the highest elevations of any non-human primate — in the high mountain forest up to 4,700 meters (15,420 feet) on a single mountain in the Nujang Lancang Gorge region.

One of the largest members of the Colobinae subfamily, black snub-nosed monkeys spend a lot of time in high evergreen trees, pick their food from trees with their hands, feeding on lichens, leaves, grass, bamboo and fruit. They are regarded as an endangered species. Their pelt was once valued as a remedy for rheumatism. Today they have suffered from loss of habitat as a result of logging. There are believed to be only between 800 and 1,200 left. [Source: Center of Chinese Academy of Sciences, kepu.net]

Black snub-nosed monkeys live at elevations between 2,625 and 4,500 meters (8,612 and 15,420 feet) and favor coniferous or mixed coniferous broad leaved forests with spruce and fir forests at an elevation between 3500-4500 meters (11,483-14,764 feet), Some groups have been seen going above 4,700 meters when foraging. After a French man found evidence of them in 1890, no news about them was heard for almost 100 years. In 1979, Kunming Institute of Zoology fond evidence of them in the snowy forests of Deqin. Since then more evidence of them has been found.

Black snub-nosed monkeys live mountain forests all year round. They are endemic to the Hengduan Mountains in southwest China and Tibet. The southernmost population was thought to be in the Yunlong Provincial Nature Reserve in Mt. Longma, but the distribution has shifted south about 40 kilometers after the discovery of a group at the Tianchi Provincial Nature Reserve. Their distribution is approximately 400 kilometers in length and 100 kilometers in width. [Source: Xin Deng, Animal Diversity Web (ADW) /=]

Black snub-nosed monkeys face a number of challenges connected with their high altitude environment: hypothermia, hypoxia (oxygen deficiency), and locating calorie-rich food during the winter. There is evidence in their genome that have several genes that have helped them adap to low amounts of oxygen. There is currently no information on the lifespan of black snub-nosed monkeys both in the wild and in captivity. However, golden snub-nosed monkeys of the same genus have a lifespan of 23 years in captivity and it is presumed that black snub-nosed monkeys live a similar length of time.

Black Snub-Nosed Monkey Characteristics and Feeding

Black snub-nosed monkeys range in weight from 6.5 to 17 kilograms (14.3 to 37.4 pounds) and range in length (their body and head) from 74 to 83 centimeters (29 to 32.7 inches). Their tail is 51-72 centimeters (20-28 inches) long. They are the most sexually dimorphic of snub-nosed monkeys, as males are 50 percent larger than females. Males average 15 to 17 kilograms, females average 9 to 12 kilograms [Source: Xin Deng, Animal Diversity Web (ADW) /=]

black snub-nosed monkey range

Black snub-nosed monkeys have features in common with other snub-nosed monkeys — characteristically thick lips and concaved nostrils. However, black snub-nosed monkeys are the only black and white snub-nosed monkeys with long hair. Males have distinguishable dark crowns of hair that droop forward, forming a crest around 9.7 to 12 centimeters long. Their faces are white with black noses and pink lips. The fur on their arms, backs, and lower legs are black, with white tufts at the elbows. A whitish-gray color fur covers their cheeks all the way down their ventral sides, covering their necks, thighs, and abdomens. The hairs around their pelvic areas and thighs are very elongated forming 20 to 21 centimeters long fringes. Compared to males, females and juveniles are not as black and have shorter hairs on their backs, crowns, and thighs. Infants are white and yellowish before they turn the lighter black color seen in juveniles. /=\

Black snub-nosed monkeys are primarily herbivores (primarily eat plants or plants parts), folivores (eat leaves) and frugivores (eat fruits). Animal foods include small mammals and eggs. Among the plant foods they eat are leaves, roots, sap, tubers, fruit and lichens. They also eat fungus Black snub-nosed monkeys primarily eat immature leaves of flowering trees in the spring, fruit in summer and fall, and lichens in the winter. Lichens are also a fallback food in seasons when leaves and fruits of flowering trees are unavailable. Black snub-nosed monkeys don’t come to ground so often but have been observed digging up mushrooms and tubers and eating rodents and bird eggs. /=\

Black Snub-Nosed Macaque Behavior

Black snub-nosed macaque are arboreal (live mainly in trees), diurnal (active mainly during the daytime), motile (move around as opposed to being stationary), nomadic (move from place to place, generally within a well-defined range), and social (associates with others of its species; forms social groups). In terms of home range, Black snub-nosed monkeys travel farther in warmer months. In a given year, the home range of bands can be 16 to 40 square kilometers. [Source: Xin Deng, Animal Diversity Web (ADW) /=]

A small black snub-nosed macaque group usually consists of one male adult, two to three female adults and some young macaques. These families hang out together in a territory that can cover tens of square kilometers. Large groups can number in the hundreds. Xin Deng wrote in Animal Diversity Web: The bands that black snub-nosed monkeys form can include up to 480 individuals that are divided into 11 to 26 units of three to 17 individuals. These units are mostly OMUs, along with one or more all-male units (AMUs). Multi-male with multi-female units are rare and do not have more than two adult males. Most aggression between OMUs is due to males defending their mates. However, findings suggest that females within OMUs compete for access to the male in the unit and that female mating success is low in larger groups. /=\

Black snub-nosed monkeys are social animals that display fission-fusion behavior, in which bands split into smaller units in response to changes in food availability, due to seasonality changes. Large bands feed as social units throughout the year, but split up at the end of a birth season, when new mothers are lactating and high quality food is in season. Splitting up and subgrouping occurs for efficient exploitation of limiting resources. /=\

black snub-nosed monkey

Black snub-nosed monkey bands travel in single-file to new sleeping and feeding sites. They travel both daily and seasonally in response to environmental variables such as temperature, slope, and sunlight. They are considered semi-nomadic (move from place to place, generally within a well-defined range), since they do not remain in already foraged areas for long, spending several hours before seeking new places to forage or sleep. Sleeping sites are often in tall trees on steep slopes, with sun exposure and protection from wind. Groups are often willing to travel long distances to sleeping sites if suitable ones are not near foraging areas. This suggests consideration of both energetic and antipredator potential. The adult male in an OMU sleeps alone, while adult females, infants, and juveniles participate in group huddling during the night. /=\

Black snub-nosed monkey groups communicate mainly with vision and sense using vision, touch and chemicals usually detected with smell. They are relatively quiet, mainly communicating using eye contact and gestures when resting and foraging. In conflicts and stressful situations, males use a distinct, loud bray, and flash their canines. When predators are near, adults emit loud alarm calls. /=\

Black Snub-Nosed Monkey Mating and Reproduction

Black snub-nosed monkeys are polygynous (males having more than one female as a mate at one time). They are also cooperative breeders (helpers provide assistance in raising young that are not their own). They engage in year-round breeding with females giving birth about once every about two years. Breeding peaks in August and September when temperatures and quality food availability are at their highest [Source: Xin Deng, Animal Diversity Web (ADW) /=]

According to Animal Diversity Web: Black snub-nosed monkeys form large groups, or bands. Within a band are units that are often one-male units (OMUs) comprised of one male with multiple females and their offspring. The adult sex ratio is skewed towards females with a 3.1:1 ratio. The relationship among OMUs are usually neutral and when aggression does occur, it is often among the adult males defending their mates. /=\

During the mating season, females initiate mating through prostration, which involves lying stretched out on the ground and repeatedly glancing at males. They sometimes also jump to get the attention of males and then present to males or sit down and move their head up and down while pausing to look at males. If solicitation is ignored, females alternate between the three behaviors in a solicitation cycle. Male solicitation involves gazing at females and baring their teeth and grunting. Ejaculatory copulation was observed less than two times a day and required multiple mounts. /=\

Black Snub-Nosed Monkey Offspring and Parenting

The gestation period for black snub-nosed monkey ranges from six to seven months. The weaning age ranges usually at least six months. Females reach sexual or reproductive maturity at four to five years and males do so at six to seven years. [Source: Xin Deng, Animal Diversity Web (ADW) /=]

With captive individuals, the birth season usually starts in March and ends in April. Because females do not start weaning infants until they are more than six months of age — during the breeding season — they do not breed the same year their child is born. In addition, evidence shows that the ratio of infants to adult females is 1:2.3, also suggesting that there is an inter-birth interval of about two years. /=\

According to Animal Diversity Web: Black snub-nosed monkey infants less than 15 days old are carried only by their mothers. By three weeks of age, mothers allow adult and juvenile females in the same OMU to provide allomaternal (not from the biological mother) care through grooming, transporting, and holding the infant. By six months of age, infants obtain most of their food by their own foraging efforts, but may still continue to nurse for an additional six to 14 months. /=\

Allomaternal nursing occurs when a lactating female provides milk for the offspring of another female. This was once observed when an infant from one OMU infiltrated another OMU. The latter OMU was not hostile to the new infant with the dominant male even transporting the non-natal infant. The infant became fully integrated into the new unit and nursed from a lactating female. The birth mother never retrieved the infant. /=\

Male allocare includes carrying infants that are not theirs when traveling. This protects infants against predators or other adult males. Male allocare peaks during energetically stressful seasons, when food is scarce. It dies down in the summer, after the birth season, when female allocare increases. /=\

Black Snub-Nosed Monkeys, Predators, Humans and Conservation

On the International Union for Conservation of Nature (IUCN) Red List Black snub-nosed monkeys are listed as Endangered. On the US Federal List they are classified as Endangered. In CITES (Convention on International Trade in Endangered Species of Wild) they are in Appendix I, which lists species that are the most endangered among CITES-listed animals and plants. [Source: Xin Deng, Animal Diversity Web (ADW) /=]

The main threat to black snub-nosed monkeys is human activities, such as logging and hunting. They are often caught accidentally by snares meant for ungulates such as deer and wild goats. The national government in China established two protected areas for black snub-nosed monkeys: the Hongla Xue Shan Mountain National Nature Reserve in Tibet and the Baimaxueshan National Nature Reserve in Yunnan. Presently, there seems to be a total 2,500 individuals known in the wild. /=\

Black snub-nosed monkeys were once hunted for food, medicine, and money. The only non-human animals known to prey are black snub-nosed monkeys are eagles and buzzards. These predators use a circle-and-wait strategy. When they detect predators, black snub-nosed monkeys drop out of view to the lower branches of trees. /=\

Image Sources: Wikimedia Commons

Text Sources: Animal Diversity Web animaldiversity.org ; National Geographic, Live Science, Natural History magazine, David Attenborough books, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Discover magazine, The New Yorker, Time, Reuters, Associated Press, AFP, Lonely Planet Guides, Wikipedia, The Guardian, Top Secret Animal Attack Files website and various books and other publications.

Last updated December 2024