Rhinopithecus roxellanagolden snub-nosed monkey

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Geographic Range

Golden monkeys, Rhinopithecus roxellana, live in the mountainous regions of southwestern China, along the Tibetan Plateau. The largest populations are found in the Wolong Natural Reserve in Sichuan Province, but the range of golden monkeys extends as far south as Gansu province.

(Emanoil, 1994; Kirkpatrick, 1995)

Habitat

Rhinopithecus roxellana is found in temperate broad leaf and conifer forests at elevations ranging from 1,600 to 4,000 m above sea level. These monkeys live in mountain forests all year long, but they may migrate to slightly lower elevations during the winter. Golden monkeys and other species in the genus Rhinopithecus are among the few primates who live in temperate zones.

(Emanoil, 1994; Kirkpatrick, 1995; Schaller, 1985)

  • Range elevation
    1,600 to 4,000 m
    to ft

Physical Description

These monkeys are reported to range from 570 mm to 760 mm in head and body length. The tail is between 510 and 720 mm. Coat color is sexually dimorphic. Males and females have a golden belly, forehead and neck. Males have grayish black on the nape, shoulders, arms, back, head and tail. In females, these parts are brownish black.

The nose is flattened, with nostrils facing forward. Two flaps of skin on the widely opened nostrils form peaks that almost touch the forehead.

(Nowak, 1999)

  • Sexual Dimorphism
  • male larger
  • Range length
    570 to 760 mm
    22.44 to 29.92 in

Reproduction

Within groups, the adult sex ratio of R. roxellana is heavily biased toward females, with a 5:1 ratio observed in some groups. This is consistent with the polygynous social organziation displayed by the monkeys. During the mating season, copulation is usually solicited by the female, who signals her estrus with proceptive behaviors, such as establishing eye contact with the male and then running a short distance away. The female also signals readiness via prostration, which involves lying with the head hanging down, the forearms stretched out or bent, the legs curled up, and the tail angling freely. Often, the prostrating female will point her anogenital region toward the male. The male responds initially with a wide opening of his mouth, and if he is interested (only about 50 percent of the time) he will mount the female. Ejaculation occurs in only a small percentage of the unions during the mating season (and it never occurs outside the mating season). For this reason, the sequence of solicitation and mounting between a male and a female may occur several times a day during the three-month mating period. Due to the scarcity of male ejaculate, a female may try to thwart the solicitation of another female to improve her chances for a successful copulation.

Golden monkeys display mating behavior throughout the year, but they breed on a seasonal basis, with all conceptions taking place within a three-month period. This period may start as early as August or as late as November, depending on the region where the monkeys live.

Once a female becomes pregnant, gestation lasts about seven months, with births occurring between April and August. Usually, one offspring is born.

(Kirckpatrick 1985, Ren et al. 1995, Schaller 1985)

Data are not available on many of the reproductive parameters of these monkeys. However, like-sized primate typically breed every year to two years, depending upon food availability. Weaning usually occurs around one year of age. In R. roxellana nursing may extend for a longer period because of the harsh climate which these animals occupy. Sexual maturity is reported to be at 4 to 5 years of age for females, and at 7 years for males.

  • Breeding interval
    The interbirth interval of these animals is not known with certainty.
  • Breeding season
    Golden monkeys breed between August and November.
  • Average number of offspring
    1
  • Average gestation period
    7 months
  • Range age at sexual or reproductive maturity (female)
    4 to 5 years
  • Average age at sexual or reproductive maturity (male)
    7 years

Mothers provide most of the care. Males have been observed grooming infants, however. Because of the social structure, which ensures that one male breeds with a group of several females, it is likely that this male, confident of his paternity, assists the females in some ways, by protecting offspring as well as by grooming them. In most primates, the period of dependence is fairly extended, and it is likely that this is the case for R. roxellana.

(Nowak, 1999)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • male
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • male
      • female
  • extended period of juvenile learning

Lifespan/Longevity

Although the lifespan of these monkeys has not been described, individuals in the related species, douc langurs (Pygathrix nameaus) are reported to have lived about 26 years in captivity. (Nowak, 1999)

Behavior

Golden monkeys are highly social animals that display a group behavior known as fission and fusion. This behavior, uncommon in primates, entails a seasonal formation of large groups alternating with a splintering into smaller groups. In the case of R. roxellana, summer groups may contain as many as 600 individuals-- an extraordinary number for any primate except humans. However, when cold weather begins to set in, the large group breaks up into subgroups of 60 to 70 individuals. The subgroups merge again in the spring. Possible factors in this phenomena include human disturbance and seasonal changes in food availability. Generally, subgroups consist of several single-male/multi-female family units, with the total number of individuals rarely falling below 40.

(Kirkpatrick 1995, Tenaza 1988)

Home Range

The typical home range for the species is 15 to 50 square kilometers

Communication and Perception

Golden monkeys are a highly vocal species, with males and females specializing in certain calls. Male vocal behavior is characterized by whines (long, wavering cries that accompany grooming and eating) and bawls (short, exhaled cries that are not situation-specific). Female vocal behavior typically consists of chucks ("ee-tcha" sounds that occur in highly stimulating contexts) and shrills (squeaks and squeals uttered in response to male whines). Both sexes indulge in other vocalizations -- grunts, sighs, moans, belches -- but to a much lesser degree. An interesting aspect of golden monkey vocalizations is the ventriloquist-like absence of any body or facial movement. This is particularly true of whines and shrills, which are often exchanged by males and females while they are eating. Captive male-female pairs of golden monkeys often vocalize in duets, not unlike those observed in some species of monogamous birds. In the wild, chorus-type vocalizations involving groups or sub-groups are common.

(Kirkpatrick 1995, Tenaza 1988)

In addition to vocalizations, these monkeys communicate with body posture (presenting for mating, etc.), and tactile communication (mounting, mating, grooming, nursing). Chemical communication has not been reported, but may be present.

Food Habits

Rhinopithecus roxellana is a largely arboreal species. The diet varies according to the season. During the warm weather months, R. roxellana feeds primarily on leaves from broad-leaf trees and fir and pine needles. Buds, bark, and fruit seeds provide supplementary nutrition. During the winter, however, these monkeys switch to a more limited diet of bark and lichen. Although the species feeds largely from arboreal sources, it will descend to the ground to feed on grasses and wild onions.

(Emanoil, 1994; Kirkpatrick, 1995; Schaller, 1985)

  • Plant Foods
  • leaves
  • wood, bark, or stems
  • seeds, grains, and nuts
  • lichens

Predation

It is not known whether other animals prey upon these primates.

Ecosystem Roles

To the extent that these animals are prey for carnivores, they may play a part in local food webs. It is likely that they affect plant growth through their herbivory.

Economic Importance for Humans: Positive

Golden monkeys are hunted by humans for fur and meat. The fur is sold for medicinal preparations and the meat is sold for food. The illegal trade of golden monkey fur makes insignificant contributions to local economies, however, and the monkey's meat provides little protein for local diets.

(Kirkpatrick 1995)

Economic Importance for Humans: Negative

These animals have no known negative effects on humans.

Conservation Status

Determining the conservation status of these animals is difficult because of the nomenclatural problems associated with them. They are listed by IUCN as vulnerable. CITES lists all Rhinopithecus species on Appendix I. Golden monkeys are also listed as endangered by the U.S. endangered species act.

Other Comments

Golden monkeys are elusive primates which have escaped close, extended study by human scientists. Most research on the species has centered on captive specimens or on limited observations of wild populations. Much about the behavior of these primates is yet to be discovered, which makes conservation all the more essential for this species. Hunting prohibitions are a step in the right direction, but more must be done to prevent further fragmentation of thismonkey's habitat.

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Peter Munoz (author), University of Michigan-Ann Arbor.

Glossary

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

drug

a substance used for the diagnosis, cure, mitigation, treatment, or prevention of disease

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

folivore

an animal that mainly eats leaves.

food

A substance that provides both nutrients and energy to a living thing.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

herbivore

An animal that eats mainly plants or parts of plants.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

polygynous

having more than one female as a mate at one time

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Emanoil, Mary ed., 1994. Encyclopedia of Endangered Species. Gale Environmental Library: Detroit, Michigan. xvii, 1230 pp.

Kirkpatrick, R.C., 1995. "The Natural History and Conservation of the Snub-Nosed Monkeys (Genus Rhinopithecus)," Biological Conservation 72: 363-369.

Ren, R., K. Yan, Y. Su, H. Qi, B. Liang, W. Bao, and F.B.M. DeWaal, 1995. "The Reproductive Behavior of Golden Monkeys in Captivity (Rhinopithecus roxellana)," Primates 36 (1): 135-143.

Schaller, R., 1985. "China's Golden Treasure," International Wildlife 15 (1): 29-31.

Nowak, R. 1999. Walker's Mammals of the World, Sixth Edition. Baltimore and London: The Johns Hopkins University Press.