Animal Diversity Web

Ge­o­graphic Range

Sil­vered leaf mon­keys, Tra­chyp­ithe­cus crista­tus, are found through­out South­east­ern Asia and In­done­sia, in­clud­ing the Malayan Penin­sula, Bor­neo, Suma­tra, Java, Thai­land, and the Natuna Is­lands. One sub­species, T. c. vig­i­lans, is found only on the Natuna Is­lands. The other sub­species, T. c. crista­tus, is found in all areas to which the species is en­demic. (Groves, 2001; Med­way, 1970)

• Biogeographic Regions
• oriental
  • native

Habi­tat

The habi­tat of T. crista­tus is very sim­i­lar to that of other mem­bers of its sub­fam­ily Colobi­nae. Sil­vered leaf mon­keys pri­mar­ily in­habit dense forests, but their habi­tat can vary some­what de­pend­ing on the re­gion. In Java and Suma­tra, they live in the trees of in­land forests, whereas on the Malaysian Penin­sula, they live in the man­grove and sub-coastal forests. They have also been found in bam­boo forests, on plan­ta­tions, and in swamp forests. Be­cause the mon­keys are largely ar­bo­real, they rarely leave the trees. Oc­ca­sion­ally, they come down to the ground, but re­treat quickly if there is a threat of dan­ger. ("Colobine Mon­keys", 2001; Fu­ruya, 1961; Med­way, 1970)

• Habitat Regions
• tropical
• terrestrial

• Terrestrial Biomes
• forest
• rainforest
• scrub forest

• Wetlands
• swamp

• Other Habitat Features
• agricultural

Phys­i­cal De­scrip­tion

Tra­chyp­ithe­cus crista­tus is sim­i­lar in ap­pear­ance to other colobines in that it is small in size, has a long tail, and dense fur. Also com­mon to colobines is an un­der-bite in which the lower jaw pro­jects out fur­ther than the upper jaw. The genus Tra­chyp­ithe­cus is dis­tin­guished from other colobines by its promi­nent nasal bones, a well-de­vel­oped coro­nal crest, and poorly de­vel­oped brow ridges. There is also a re­duc­tion in the size of the first digit (thumb) fa­cil­i­tat­ing the brachi­at­ing move­ments they uti­lize. The fore and hind limbs are more equal in length than most other cer­co­p­ithe­cids, or Old World Mon­keys, sug­gest­ing that the group pre­vi­ously oc­cu­pied a more ter­res­trial habi­tat. (Nowak, 1999)

Sil­vered leaf mon­keys get their name from the col­or­ing of their pelage. There is some vari­a­tion in the color of their fur, in­clud­ing brown, gray, brown­ish-gray, or black. No mat­ter what the color, some hairs are gray-white and give a sil­ver ap­pear­ance. Poly­mor­phisms are very rare; the best known is a red morph that ex­ists in Bor­neo. The hands and feet are pre­hen­sile, hair­less, and usu­ally black in color. Males and fe­males are dif­fi­cult to dis­tin­guish from one an­other. The only vis­i­ble dif­fer­ence is ir­reg­u­lar white patch­ing on the in­side of the flanks of fe­males. Males are also slightly larger than fe­males: fe­males are 89% of the body weight of the males. (Fu­ruya, 1961; Med­way, 1970; Roon­wal, 1977)

New­borns have or­ange fur and white col­ored hands, feet, and face. The skin changes color within days of birth to black, as in the adults of this species. The or­ange fur changes to the adult color within three to five months. (Roon­wal, 1977)

Body length in males ranges from 52.4 cm to 56.0 cm, whereas fe­males are typ­i­cally 46.5 cm to 49.6 cm. Both sexes have a tail that is longer than their body; tail length ranges from 63 cm to 84 cm. Male body weight av­er­ages 7.1 kg and fe­male body weight is about 6.2 kg. New­borns are about 20 cm and 0.4 kg at birth. They reach their adult size at about 5 years of age. (Roon­wal, 1977)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• sexes alike
• male larger

• Range mass

  4.9 to 8.0 kg

  10.79 to 17.62 lb

• Average mass

  Male: 7.1; Female: 6.2 kg

  lb

• Range length

  46.5 to 56.0 cm

  18.31 to 22.05 in

Re­pro­duc­tion

Groups of T. crista­tus are gen­er­ally one-male groups in which one male de­fends and mates with mul­ti­ple fe­males. All-male groups as well as sin­gle males are also found. Oc­ca­sion­ally, a male from an all-male unit or an in­di­vid­ual male will chal­lenge the male of a male/fe­male group. If the chal­lenger pre­sides over the de­fend­ing male, in­fan­ti­cide usu­ally oc­curs. Fe­males com­monly care for young of other moth­ers in the group, and often even allow other young to nurse. (Fu­ruya, 1961; Med­way, 1970; Roon­wal, 1977)

• Mating System
• polygynous
• cooperative breeder

Tra­chyp­ithe­cus crista­tus re­pro­duc­tion has not been widely stud­ied, how­ever a few facts are known. There is no lim­ited sea­son for cop­u­la­tion, al­though there is a birth peak from De­cem­ber to May when there is an abun­dance of food. The ges­ta­tion pe­riod is 6 to 7 months, and the es­trous cycle is 24 days. Fe­males usu­ally give birth to no more than one in­fant per year. Twins have oc­curred, but are very rare. Fe­males reach sex­ual ma­tu­rity at 4 years of age, whereas males ma­ture be­tween 4 and 5 years of age. ("Colobine Mon­keys", 2001; Roon­wal, 1977)

• Key Reproductive Features
• iteroparous
• year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
• viviparous

• Breeding interval

  Silvered leaf monkeys typically breed once every year.

• Breeding season

  Breeding does not appear to be strictly limited by season.

• Average number of offspring

  1

• Average number of offspring

  1

  AnAge

• Average gestation period

  6 months

• Average age at sexual or reproductive maturity (female)

  4 years

• Average age at sexual or reproductive maturity (female)
  Sex: female

  1461 days

  AnAge

• Average age at sexual or reproductive maturity (male)

  4-5 years

There is lit­tle in­for­ma­tion avail­able about parental care of young, how­ever, being mam­mals, sil­vered leaf mon­keys in­vest a great deal of time and care into off­spring. Moth­ers nurse their young for months after birth. Fe­males, as well as males, teach their young, play with them, and pro­tect them from dan­ger. How­ever, typ­i­cally in­fants ap­proach males to be car­ried and to play. Young are well de­vel­oped when born. Their eyes are open and their fore­arms are strong, al­low­ing them to cling to the mother. (Fu­ruya, 1961; Roon­wal, 1977)

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

Lifes­pan/Longevity

The lifes­pan of T. crista­tus has rarely been recorded. In cap­tiv­ity, the max­i­mum lifes­pan is 29 years. An­i­mals in the wild gen­er­ally live about 20 years, al­though due to dif­fi­culty in mak­ing sus­tained ob­ser­va­tions in the wild, exact longevity in the wild is un­known. ("Colobine Mon­keys", 2001; Nowak, 1999)

• Average lifespan
  Status: wild

  20 years

• Range lifespan
  Status: captivity

  29 (high) years

• Average lifespan
  Sex: female
  Status: captivity

  31.1 years

  Max Planck Institute for Demographic Research

Be­hav­ior

The be­hav­ior of T. crista­tus is not well known. Like many pri­mates, T. crista­tus is a so­cial species. In­di­vid­u­als form groups con­sist­ing of one male and 9 to 48 fe­males, de­pend­ing on the lo­ca­tion. Ju­ve­niles usu­ally dis­perse from their natal group at ma­tu­rity. Being di­ur­nal, the ma­jor­ity of ac­tiv­ity for this species is from sun­rise to sun­set. Tra­chyp­ithe­cus crista­tus is a very shy species. In­di­vid­u­als are oc­ca­sion­ally seen in the vicin­ity of human set­tle­ments, but re­treat quickly if they feel threat­ened. (Fu­ruya, 1961; Med­way, 1970; Nowak, 1999; Roon­wal, 1977)

Tra­chyp­ithe­cus crista­tus trav­els pri­mar­ily via brachi­a­tion, al­though in­di­vid­u­als may walk on the ground when trav­el­ing with the group. They show a low level of ag­gres­sion within the so­cial group. So­cio­sex­ual, ges­tural, and vocal in­ter­ac­tions are the com­mon fea­tures of the so­cial re­la­tion­ships of these mon­keys. This may be due to the abun­dance of food in their habi­tat and their feed­ing be­hav­ior of fac­ing to­ward the tree while eat­ing. These both de­crease the fre­quency of in­ter­ac­tion with other mem­bers of the group, re­sult­ing in less need for tight group co­op­er­a­tion.

Al­though the species is fairly peace­ful, there is oc­ca­sion­ally con­flict with neigh­bor­ing groups of the same species over ter­ri­tory. Many times, the groups will live in peace with each other in close prox­im­ity after the ini­tial con­flict. There is some ag­gres­sion within groups, and this may be re­lated to sex. Gen­er­ally, there are only in­traspe­cific con­flicts. Tra­chyp­ithe­cus crista­tus tends to co-ex­ist com­fort­ably with other species such as Macaca fas­ci­c­u­laris that in­habit the same re­gions. ("Colobine Mon­keys", 2001; Med­way, 1970; Nowak, 1999; Roon­wal, 1977)

• Key Behaviors
• arboreal
• scansorial
• diurnal
• motile
• nomadic
• sedentary
• territorial
• social

Home Range

Be­cause this is a no­madic species, sil­vered leaf mon­keys travel about 200 to 500 me­ters through­out their ter­ri­tory daily. The male of the group leads the fe­males while guid­ing them with vo­cal­iza­tions. The ter­ri­tory a group oc­cu­pies av­er­ages 43 hectares. (Med­way, 1970)

Com­mu­ni­ca­tion and Per­cep­tion

Tra­chyp­ithe­cus crista­tus is the most silent of the colobine species. Re­searchers de­scribe these mon­keys as being grave, se­ri­ous, ex­pres­sion­less, and slow mov­ing. They make 13 dif­fer­ent vo­cal­iza­tions, which are most com­mon at dusk and dawn. They vo­cal­ize to sig­nal con­flict, fear, warn­ings, alarms, and salu­ta­tion. In ad­di­tion to these vo­cal­iza­tions, males make threat­en­ing calls and young call for their moth­ers. Al­though mem­bers of the species are rel­a­tively quiet, in­di­vid­u­als also com­mu­ni­cate non­vo­cally with each other in so­cial play, groom­ing, and light fight­ing. (Fu­ruya, 1961; Med­way, 1970; Roon­wal, 1977)

• Communication Channels
• visual
• tactile
• acoustic
• chemical

• Perception Channels
• visual
• tactile
• chemical

Food Habits

Sil­vered leaf mon­keys, as their name sug­gests, feed pri­mar­ily on leaves, with a pref­er­ence for young leaves. As her­bi­vores, they also eat some other veg­e­ta­tion in­clud­ing fruit, seeds, shoots, flow­ers, and buds. Some adap­ta­tions have been made to in­crease ef­fi­ciency of di­gest­ing and pro­cess­ing plant ma­te­ri­als. The teeth have pointed cusps on their two trans­verse ridges, and are re­ferred to as bilophodont. The stom­ach has be­come sac­cu­lated and con­tains bac­te­ria for fer­men­ta­tion of the plants. The stom­ach is also en­larged to hold a large amount of food, given that the food they eat is nu­tri­tion­ally poor. They also con­tain large sali­vary glands that act to neu­tral­ize stom­ach acid that may cause dam­age if seep­age from the stom­ach oc­curs. ("Colobine Mon­keys", 2001; Groves, 2001)

• Primary Diet
• herbivore
  • folivore

• Plant Foods
• leaves
• seeds, grains, and nuts
• fruit
• flowers

Pre­da­tion

Preda­tors of sil­vered leaf mon­keys are com­mon preda­tors found through­out the forests of south­east Asia, Thai­land, and In­done­sia, and in­clude snakes, tigers, lea­pords, and jack­als. The for­est canopy is the safest place for T. crista­tus as there are no rap­tors in the area that prey on ar­bo­real mon­keys. There­fore, the tree­tops act as pro­tec­tion for sil­vered leaf mon­keys. (Med­way, 1969; Streck, 2002)

• Known Predators

  • Canis
  • Neofelis nebulosa
  • Panthera tigris
  • Python reticulatus

Ecosys­tem Roles

Like most other mem­bers of their genus, T. crista­tus feeds on young leaves. How­ever, their im­pact on their ecosys­tem is un­known. ("Colobine Mon­keys", 2001)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Many pri­mates are hunted by hu­mans in Asia for their flesh and the med­i­c­i­nal value of be­zoar stones found in their in­tes­tine. Tra­chyp­ithe­cus crista­tus, how­ever, is the ex­cep­tion. Other as­pects of this species that may pos­i­tively af­fect hu­mans are un­known. ("Colobine Mon­keys", 2001)

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Neg­a­tive im­pact on hu­mans is un­known and un­likely due to the rar­ity of these an­i­mals and the in­fre­quency of in­ter­ac­tion with hu­mans.

Con­ser­va­tion Sta­tus

Sil­vered leaf mon­keys are con­sid­ered threat­ened ac­cord­ing to IUCN RedList and are on the CITES Web­site, Ap­pen­dix II. The species was first la­beled threat­ened in 1996. Their sta­tus is threat­ened due to the habi­tat de­struc­tion oc­cur­ing in the forests of their re­gion for agri­cul­ture. (Nowak, 1999)

• IUCN Red List

  Near Threatened
  More information

• IUCN Red List

  Near Threatened
  More information

• CITES

  Appendix II

Other Com­ments

Tra­chyp­ithe­cus crista­tus has dif­fer­ent com­mon names in dif­fer­ent coun­tries. In Eng­lish, they are re­ferred to as sil­vered leaf mon­keys, whereas in India they are re­ferred to as sil­vered lan­gurs. In their en­demic area of Malaya, they are called lu­tong. (Fu­ruya, 1961)

Sir Thomas Stam­ford Raf­fles orig­i­nally de­scribed the species in 1821. He gave them the name Simia cristata. The sci­en­tific name was later changed to Pres­bytis crista­tus. The genus Pres­bytis has been bro­ken into 4 new groups, in­clud­ing the genus Tra­chyp­ithe­cus, in which T. crista­tus is now found. The mean­ing of the name Tra­chyp­ithe­cus comes from the Greek words "trach," mean­ing rough and "pithekos," mean­ing ape. Crista­tus comes from the Latin word "crista," which means crest or tuft. Thus, the name was given fit­ting its phys­i­cal char­ac­ter­is­tics. ("Colobine Mon­keys", 2001; Fu­ruya, 1961)

Con­trib­u­tors

Chris­tine Bedore (au­thor), Michi­gan State Uni­ver­sity, Bar­bara Lun­dri­gan (ed­i­tor, in­struc­tor), Michi­gan State Uni­ver­sity, Nancy Shef­ferly (ed­i­tor), An­i­mal Di­ver­sity Web.

Ref­er­ences

2001. Colobine Mon­keys. Pp. 380-391 in D Mac­Don­ald, ed. En­cy­clo­pe­dia of Mam­mals, Vol. 2, 2 Edi­tion. New York: An­drom­eda Ox­ford Lim­ited.

Wis­con­sin Re­gional Pri­mate Re­search Cen­ter, Uni­ver­sity of Wis­con­sin, Madi­son. 2004. "Pri­mate Info Net" (On-line). Ac­cessed Feb­ru­ary 24, 2005 at http://​pin.​primate.​wisc.​edu/​.

Fu­ruya, Y. 1961. The So­cial Life of Sil­vered Leaf Mon­keys (Tra­chyp­ithe­cus crista­tus) . Pri­mates, 3(2): 41-60.

Groves, C. 2001. Pri­mate Tax­on­omy. Wash­ing­ton: Smith­son­ian In­sti­tu­tion Press.

Groves, C., R. Thor­ing­ton. 1970. An An­no­tated Clas­si­fi­ca­tion of the Cer­co­p­ithe­coidea. Pp. 629-644 in Old World Mon­keys: Evo­lu­tion, Sys­tem­at­ics, and Be­hav­ior. Lon­don: Aca­d­e­mic Press.

Groves, C., V. Weitzel. 1985. The Nomen­cla­ture and Tax­on­omy of the Colobine Mon­keys of Java. In­ter­na­tional Jour­nal of Pri­ma­tol­ogy, 6: 399-409.

Harper, D. 2001. "On­line Et­y­mol­ogy Dic­tio­nary" (On-line). Ac­cessed Feb­ru­ary 28, 2005 at http://​www.​etymonline.​com.

Med­way, L. 1970. The Mon­keys of Sun­da­land: Ecol­ogy and Sys­tem­at­ics of the Cer­co­p­ithe­cids of a Humid Equa­to­r­ial En­vi­ron­ment. Pp. 513-554 in Old World Mon­keys: Evo­lu­tion, Sys­tem­at­ics, and Be­hav­ior. Lon­don: Aca­d­e­mic Press.

Med­way, L. 1969. The Wild Mam­mals of Malaya. Lon­don: Ox­ford Uni­ver­sity Press.

Nowak, R. 1999. Walker's Mam­mals of the World. Bal­ti­more: Johns Hop­kins Uni­ver­sity Press.

Roon­wal, M. 1977. Pri­mates of South Asia: Ecol­ogy, So­cio­bi­ol­ogy, and Be­hav­ior. Cam­bridge: Har­vard Uni­ver­sity Press.

Streck, E. 2002. Preda­tor Sen­si­tive For­ag­ing in Thomas Lan­gurs. Pp. 76 in L Miller, ed. Eat or Be Eaten: Preda­tor Sen­si­tive For­ag­ing Among Pri­mates. Cam­bridge: Cam­bridge Uni­ver­sity Press.