Delacour's Langur (Trachypithecus delacouri)


MORPHOLOGY:
This species has a sacculated stomach to assist in the breakdown of cellulose. Delacour's 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 Delacour's langur is 2:1:2:3 on both the upper and lower jaws (Ankel-Simons, 2000). The pelage coloration of this species is glossy black with white to cream-colored hair on the thighs running across the lower back (Rowe, 1996). The color of the face is black with white from the corners of the mouth to the ears on both sides of the face (Rowe, 1996). The tail is long and the hair is especially long on the middle part of the tail (Rowe, 1996). Newborns are a brown coloration and have more white on the head (Rowe, 1996).

RANGE:
Delacour's langur is found in the country of Vietnam (Adler, 1991; Le and Campbell, 1993/1994; Weitzel and Vu, 1992; Le, 1996/1997). This species is found in Cuc Phuong National Park, Ha Nam province (Adler, 1991). Delacour's langur has also been reported from Thanh Hoa province (Weitzel and Vu, 1992). Nadler (1996) also found this species to occur in the provinces of Hoa Binh, Ninh Binh, and Nghe An. This species lives in forests around limestone cliffs, karst forests (Nadler, 1996; Rowe, 1996).

ECOLOGY:
Delacour's langur is a folivorous species (Nadler, 1996). This is an arboreal and diurnal species. During the day, groups will rest several times, individuals remaining motionless and silent (Nadler, 1996). Groups will sleep in the caves of the limestone cliffs found in their area (Nadler, 1996). A group will use one cave for several nights then move to another, utilizing from three to five caves in the home range (Nadler, 1996). Groups will arrive to the caves after dark and leave before the sun rises (Nadler, 1996). Humans, Homo sapiens, are the main predator of this species (Adler, 1991; Nadler, 1994, 1996).

LOCOMOTION:
Delacour's langur moves through the forest quadrupedally (Fleagle, 1988). The young of this species are more likely to use suspensory locomotive movements than adults (Workman and Covert, 2002).

SOCIAL BEHAVIOR:
Delacour's 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:
Delacour's langur gives birth to a single offspring.

REFERENCES:
Adler, H.J. 1991. On the situation of the Delacour's langur (Trachypithecus f. delacouri) in the north of Vietnam - proposal for a survey and conservation project. Primate Report. Vol. 31, 6-7.

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. 1996/1997. Endangered primate species in Vietnam. Primate Conservation. Vol. 17, 117-126.

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. 1994. The Delacour langur in Vietnam. Nhan Dan. Vol. 264, 6.

Nadler, T. 1996. Report on the distribution and status of Delacour's langur (Trachypithecus delacouri). Asian Primates. Vol.6(1-2), 1-4.

Rowe, N. 1996. The Pictorial Guide to the Living Primates. Pogonias Press: East Hampton, New York.

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

Workman, C. and Covert, H.H. 2002. A comparison of the positional behavior of infant and adult red-shanked douc langurs, Delacour's langurs, and Hatinh langurs at the Cuc Phuong Endangered Primate Rescue Center, Vietnam. XIX Congress of the International Primatological Society. Beijing, China, 0286.

Last Updated: June 20, 2007.
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