Francois' langur

Francois' langur[1]
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Cercopithecidae
Genus: Trachypithecus
Species group: T. francoisi
Species: T. francoisi
Binomial name
Trachypithecus francoisi
(de Pousargues, 1898)
Geographic range

Francois' langur or Francois' leaf monkey (Trachypithecus francoisi) is a species of lutung and the type species of its species group. Francois' langur belongs to the Colobinae subfamily, Cercopithecidae family, in the Primates order.[3] Of all of the colobine species, Francois' langur is the least studied of all of the species.[4]

The species is distributed from Southwestern China to northeastern Vietnam. Before 1990, Francois' Langur could be found in 23 different countries with a total population size of 2,000-2,500 individuals.[5] There has been a dramatic decline in the population size by approximately 85% since then, making this species that of very high priority to potential extinction.[5] The total number of wild individuals is unknown, but there are believed to be less than 500 left in Vietnam and 1,400-1,650 in China.[2] There are only about 60 langurs in captivity in North American zoos.

The Mesker Park Zoo in Evansville, Indiana, has made headlines for its success in breeding the rare monkey. The zoo received two females, Liang and Sai, in November 2003 from the San Diego Zoo. Each gave birth to a son in August 2006. The father came from the Cincinnati Zoo in December 2005. In February 2008 Liang gave birth to a female.[6]

In March 2009 an orange female was born at Australia's Taronga Zoo. She is being cared for by zoo staff after being rejected by her mother.[7] http://www.cutebreak.com/?s=elke&submit.x=0&submit.y=0&submit=Submit+now

In September 2009 a female (GinLu) was born in the Lied Jungle at Omaha's Henry Doorly Zoo. After being rejected by her mother, Lied Jungle keepers worked for several weeks to teach the mother to feed and care for her properly. It was important to have a special holding area for mother and infant for safety, ensuring the family was within sight and smell at all times. Mother and infant needed to be strongly bonded before placing the group together. By October 13, 2009, the entire group was reunited into one holding area.[8]

Contents

Range and Distribution

Francois' langur has a restricted range of areas in which it can inhabit. It is primarily found in South West China and Northern Vietnam. A majority of the observations made on Francois' Langur take place in the Nonggang nature Reserve and the Fusui Nature Reserve in Guangxi Province, China.[9] The average home range size of this species is 19ha and its day range size is 341-577m2.[9] In general, the low quality of its folivorous diet leads to nutritional stress, a smaller home range size and reduced daily travel time. The largest group of langurs reported numbered 500-600 individuals, and was found in the Mayanghe National Nature Reserve.[3] The Fusui nature Reserve reported in 2009 that Francois' langur population had declined 73% in the previous 5 years, thus lessening their distribution even more.[9]

Physical description

Francois' langur is a medium sized primate with black silky hair. It grows to be approximately 24 inches tall with a tail length of approximately 33 inches. The average weight for an adult Francois' langur is 13-15 lbs.[10] It has very distinct white sideburns that grow down from its ears to the corners of its cheeks. A morphological specialization of Francois' langur is its complex stomach, made up of four separate chambers. This is a necessary adaptation for the digestion of its folivorous diet.[4]

Social structure

Francois' langur tends to live in groups of four to seven langurs, the mean being seven. [9] "In [Francois] Langur society, females rule the roost and take the lead when the family is on the move" (BBC-Wild China, Episode 1). It lives in harem societies with a group consisting of one male, three females, and three offspring. Within the society, the females will share parenting responsibilities with one another and are philopatric to the group.[9] Males within the group take no part in the raising of the young, the young males will leave the group before reaching sexual maturity.[9]

Behavior

Francois' langur is one of several species of leaf monkeys. Over 50% of its diet is made up of young leaves.[4] It will also consume fruits (17.2%), seeds, flowers, stems, roots, bark and occasionally minerals and insects off of rock surfaces and cliffs.[4] This langur consumes its favorite food, young leaves, at the highest rate during the dry season, April through September, also known as the young leaf-lean period.[4] The consumption of other dietary options for the langur is typically consumed in the highest amounts during the months of October through March.

Langurs not only prefer young leaves, but also have been found to prefer plants of only 10 different species: Pithecellobium clypearia, Ficus nervosa, Garcinia pauncinervis, Sinosideroxylon pedunculatum, F. microcarpa, Miliusa chunni, Securidaca inappendiculata, Bauhinia sp., and Canthium dicoccum.[4] Though these are the preferred plant species of the langur, it will still consume other plant species opportunistically.

Behavioral daily activities vary in the Francois' Langur. Most of its time is spent relaxing or sleeping and foraging year around.[3] Traveling, playing, grooming and huddling are more dependent on the season.[11] Interestingly it has been found that grooming happens in all of the seasons except the spring where it has been seen to not happen at all. Traveling is at its highest peak in the winter season, consuming 20.12% of its daily time budget. Lastly huddling is most prominent in the spring; it is most common to observe this langur spending approximately 14.62% of its time huddling.[11]

Its preferred habitat is a karst topography; limestone cliffs and caves of tropical and subtropical zones.[5] By living on these limestone cliffs, langurs are at an advantage when it comes to sleeping arrangements. Langurs sleep either on a ledge or in a cave, with its preference being in the cave.[12] By living and sleeping in these limestone caves and cliffs, far from flat land, the langurs have greatly reduced their rate of predation. They exhibit cryptic behavior and become very vigilant upon entrance of the cave for final resting as a tactic to warn off any predators.[12] In addition to this they also demonstrate a loud call to declare their territorial spacing.[13] Francois' langurs will also choose their sleeping habitat depending upon foraging availability. They will choose sleeping sites that are close to potential foraging sites, to maximize energy and reduce travel costs. When they do go to forage they tend to travel along the same route and return to the same sleeping site for many consecutive nights to avoid predation.[12]

Threats and Conservation

The population of Francois' langur has been on a steady decline for the past 30 years. Of the many factors threatening the survival of the Francois' langur today, hunting has had one of the largest impacts.[5] In Nonggang, where Francois' Langur is most prevalent, the natives believe that the langur had medicinal values, and have hunted them to make wine out of their bones, which they believed could cure fatigue and rheumatism.[5] In 1983, the estimated population of Francois' langur was 4,000-5,000. In the 1970s, hunting records recorded more than 1,400 langurs killed and in the 1980s more than 1,500 langurs were killed. Comparing these numbers it is evident how hunting had an enormous impact on Francois' Langur population.

Another threat to Francois' langur is the destruction of its habitat. The langurs live on limestone cliffs and when farmers look to cultivate their land they will light fires on the lower slopes. Limestone is particularly susceptible to fire; therefore this practice not only destroys their habitats but also causes major food shortages for the langurs because their diet is primarily folivorous.[5] The primary predators of Francois' langur are both terrestrial and aerial.[12] The Clouded Leopard is a potential predator to the langur but the Clouded Leopard's numbers are so low that they are not their greatest threat. Aerial predators such as the Crested Serpent Eagle and the Mountain Hawk-eagle are a greater threat to the Francois' langurs of Nonggang, especially to their young.[12]

The actions being taken towards the conservation of these animals and their habitat is still minimal. Their current population size is less than 2,500 individuals.[5] A plan to protect the forest and ban hunting, called the Conservation Action Plan, was drafted in 1996 but has still yet to be implemented. In order to protect the langurs, not only does protection from hunting need to be implemented but their habitats must be protected as well. In 2003, the National Forestry Bureau acknowledged the rapid decline in Francois' Langur and agreed to increase law enforcement in this area to help protect the langurs from hunters.[5] In addition, the Asia Developmental Bank has begun helping the residents that live in close proximity to the habitats of the langurs build biogas facilities to reduce the fuel wood collection and thus possibly reduce the number of fires.[5] And finally, a current project is underway by the Global Environmental facility to protect the Nonggang National and Dmingshan Natural Reserves and the langurs living within.[5]

References

  1. ^ Groves, C. (2005). Wilson, D. E., & Reeder, D. M, eds. ed. Mammal Species of the World (3rd ed.). Baltimore: Johns Hopkins University Press. OCLC 62265494. ISBN 0-801-88221-4. http://www.bucknell.edu/msw3/browse.asp?id=12100715. 
  2. ^ a b Bleisch, B., Manh Ha, N., Khat Quyet, L. & Yongcheng, L. (2008). Trachypithecus francoisi. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 4 January 2009.
  3. ^ a b c Yang, Lou, Minghai, Z., Jianzhang, M., Ankang, W., Shusen, Z. (2007). "Time budget of daily activity of Francois’ langur (Trachypithecus francoisi) in disturbance habitat". Acta Ecologica Sinica 27: 1715–1722. doi:10.1016/S1872-2032(07)60043-2. 
  4. ^ a b c d e f Zhou, Qihai, Fuwen, W., Li, M., Chengming, H., Luo, B. (2006). "Diet and food choice of (Trachypithecus francoisi) in the Nonggang Nature Reserve, China". International Journal of Primatology 27: 1441–1458. doi:10.1007/s10764-006-9082-8. 
  5. ^ a b c d e f g h i j Li, Youbang, Huang, C., Ding, P., Tang, Z., and Wood. (2007). "Dramatic Decline in the Francois’ langur (Trachypithecus francoisi) in Guangxi Province, China". Oryx 41: 38–43. doi:10.1017/S0030605307001500. 
  6. ^ "New Zoo Arrival". Evansville Courier & Press. http://www.courierpress.com/news/2008/feb/08/new-zoo-arrival/. Retrieved 2008-10-14. 
  7. ^ Robinson, Kelly (2009-03-24). "Endangered francois langur Elke makes debut at Taronga Zoo". news.com.au. http://www.news.com.au/story/0,27574,25235107-421,00.html. Retrieved 2009-03-24. 
  8. ^ Husman, Steph (2009-12-30). "A Francois Langur Population Increase at Omaha'a Henry Doorly Zoo". http://www.zandavisitor.com/newsarticle-2778. 
  9. ^ a b c d e f Zhou, Qihai, Chengming, H., Li, Y., Cai, X. (2007a). "Ranging behavior of the Francois’ langur (Trachypithecus francoisi) in the Fusui nature Reserve, China". Primates 48 (4): 320–323. doi:10.1007/s10329-006-0027-9. PMID 17171396. 
  10. ^ Pate, Dennis. 1998. Francois langur 98’ Fact Sheet. American Zoo and Aquarium Association.
  11. ^ a b Zhou, Qihai, Wei, F., Chengming, H., Li, M., Ren, B., Luo, B. (2007b). "Seasonal Variation in the Activity Patterns and Time Budgets of Trachypithecus francoisi in the Nonggang Nature Reserve, China". International Journal of Primatology 28: 657–671. doi:10.1007/s10764-007-9144-6. 
  12. ^ a b c d e Zhou, Qihai, Chengming, H., Ming, L., Fuwen, W. (2009). "Sleeping Site Use by Trachypithecus francoisi at Nonggang Nature Reserve China". International Journal of Primatology 30: 353–365. doi:10.1007/s10764-009-9348-z. 
  13. ^ Li, Zhaoyuan and E. Rogers. (1993). "Time budgets of Presbytis leucocephalus". Acta Theriol Sin 12: 7–13.