Golden-headed Langur (Trachypithecus poliocephalus)


MORPHOLOGY:
This species has a sacculated stomach to assist in the breakdown of cellulose. The golden-headed langur has enlarged salivary glands to assist it in breaking down food. This species has slim hands and feet and reduced thumbs. The dental formula of the golden-headed langur is 2:1:2:3 on both the upper and lower jaws (Ankel-Simons, 2000). The body mass of the golden-headed langur ranges from 15 to 20 kilograms (Le and Campbell, 1993/1994). The head and body length of this species ranges from 492-590 millimeters (Groves, 2001). The tail length of this species ranges from 820-887 millimeters (Groves, 2001). Individuals have hair on the head, shoulders, and rump that ranges in color from orange to silver (Le and Campbell, 1993/1994). The thighs of this species are grayish in coloration (Weitzel and Vu, 1992). The hairs of the crest and sometimes back to the nape are black-tipped (Groves, 2001). Both sexes have pale orange to pale yellow hairs in the pubic region (Groves, 2001). Sexual dichromatism may occur where the male has lighter colored hair on the shoulders and rump (Le and Campbell, 1993/1994).

RANGE:
The golden-headed langur is found in the country of Vietnam (Le and Campbell, 1993/1994). This species is only known to occur on Cat Ba Island in Vietnam (Le and Campbell, 1993/1994; Weitzel and Vu, 1992; Nadler, 2001; Groves, 2001). This species lives in forests around limestone formations, at an elevation from 70-100 meters (Le and Campbell, 1993/1994).

ECOLOGY:
The golden-headed langur is a folivorous species. This is an arboreal and diurnal species. The average number of group members is 4.4 individuals (Le and Campbell, 1993/1994).

LOCOMOTION:
The golden-headed langur moves through the forest quadrupedally (Fleagle, 1988). When moving up cliffs, the tail of this species is held in an "S" configuration below the level of the pelvis (Le and Campbell, 1993/1994).

SOCIAL BEHAVIOR:
The golden-headed langur has a unimale social system.

VOCAL COMMUNICATION:

OLFACTORY COMMUNICATION:

VISUAL COMMUNICATION:

TACTILE COMMUNICATION:
social grooming: This is when one individual grooms another and is used to reinforce the bonds between individuals.

REPRODUCTION:
The golden-headed langur gives birth to a single offspring. The breeding season of this species is probably in April (Le and Campbell, 1993/1994).

REFERENCES:
Ankel-Simons, F. 2000. Primate Anatomy. Academic Press: San Diego.

Fleagle, J. G. 1988. Primate Adaptation and Evolution. Academic Press: New York.

Groves, C.P. 2001. Primate Taxonomy. Smithsonian Institute Press: Washington, D.C.

Le, X.C. and Campbell, B. 1993/1994. Population status of Trachypithecus francoisi poliocephalus in Cat Ba National Park. Asian Primates. Vol. 3(3/4), 16-20.

Nadler, T. 2001. Status and action plan pf the golden-headed langur (Trachypithecus poliocephalus) - the world's rarest primate. (abstract) XVIII Congress of the International Primatological Society. Adelaide, Australia.

Weitzel, V. and Vu, N.T. 1992. Taxonomy and conservation of Trachypithecus francoisi in Vietnam. Asian Primates. Vol. 2(2), 2-5.

Last Updated: June 20, 2007.
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