Rhinoceros sondaicusJavan rhinoceros

Geographic Range

Rhinoceros sondaicus (Javan rhinoceros) is known to reside in only two Southeast Asian locales: Ujung Kulon National Park in Java, Indonesia, and Cat Tien National Park in Vietnam. Approximately 50 to 60 Javan rhinoceroses are living in Ujung Kulon; while a small group consisting of only 7 to 15 individuals are thought to be living in Cat Tien.

Habitat

Rhinoceros sondaicus resides in dense, low-lying tropical rainforests. They prefer areas with abundant water and mud wallows. Although most members of the species are found in these lowland areas, they have been observed at more than 1000 feet above sea level.

Physical Description

An average adult Javan rhinoceros is approximately 11 to 12 feet in length, with a height of 5 to 6 feet to the top of its shoulders. There is little sexual dimorphism. They are known for having poor eyesight, but they have keen senses of smell and hearing -- despite having smaller ears than other rhinoceroses. The skin is a hazy grey and contains tough folds that create an armor-like plating. Its one horn is made up of keratin (as are human fingernails), and may grow to a length of 10 inches. Females may lack a horn. Each foot ends in three hooved toes. Their teeth are lophodont, and the Javan rhinoceros also has an unique prehensile lip that functions as an aid for feasting on leaves.

  • Range mass
    900 to 1400 kg
    1982.38 to 3083.70 lb

Reproduction

The female Javan rhinoceros reaches sexual maturity at three to four years of age, while males reach maturity after six years. The gestation period is sixteen months, and the interval between births is four to five years. One rhinoceros is born at a time. A young rhino will be active shortly after birth, and will be suckled by its mother for one to two years. Thirty-five to forty years is the average lifespan of Javan rhinoceroses.

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • Average number of offspring
    1
    AnAge
  • Average gestation period
    502 days
    AnAge
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    1278 days
    AnAge

Lifespan/Longevity

Behavior

The Javan rhinoceros is fairly solitary, except for mating pairs and mothers with their young. The range for the rhinoceros extends between 3 to 20 square miles, with various groups having ranges that overlap one another. There is no set mating season.

Communication and Perception

Food Habits

Rhinoceros sondaicus feeds for the most part by browsing. In addition to this, the Javan rhinoceros is known to graze upon leaves, young shoots, twigs and fruit.

Economic Importance for Humans: Positive

Eastern Asian medicine views rhino horns as an important, if not essential part, of medicine. Sixty percent of Eastern Asian doctors stock rhino horn, with Asian horns being perferred over their African counterparts. In this part of the world, one kilogram of rhino horn sells for approximately $60,000. The tribal people of Vietnam are also known to poach the rhinoceros for meat.

Economic Importance for Humans: Negative

Many people in the Javan rhinoceros' homelands, especially Vietnam, would like to see the land upon which the rhino lives cleared for agricultural purposes. As long as governments protect these lands, agriculture can not occur here.

Conservation Status

The Javan rhinoceros is one of the most endangered species of the rhinoceros family (along with the Sumatran rhinoceros), and one of the rarest large mammals in the world. Following the Vietnam war, Rhinocerous sondaicus was thought to be extinct in Vietnam. Agent Orange, land mines, and general warfare decimated the rhinocerous population. Only recently was the Javan rhinocerous spotted in the area. With such a small population however, the prospects for survival are not good. Although the land on which they live is currently protected, there is pressure to use the land for agricultural purposes. In addition, it is not known how many of the 7 to 15 rhinos are females. If there are only 1 or 2 females, their death could mean the end of the species in Vietnam. Also, with so few animals, the likelihood of inbreeding is great. Inbreeding is known to increase the likelihood of birth defect or disease. Those Javan rhinoceroses residing in Indonesia are fortunate to have a slightly larger population. However, should an environmental catastrophe (such as a forest fire) or disease affect the population, dire consequences could result.

Other Comments

Rhinoceros sondaicus is also referred to as the lesser one-horned rhinoceros.

There are currently no Javan rhinoceroses in captivity.

Contributors

Michael Waters (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

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

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.

motile

having the capacity to move from one place to another.

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

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

sexual

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

tactile

uses touch to communicate

References

"Facts" (On-line). Accessed October 13, 1999 at http://www.sosrhino.org.

"IRF Rhino Information: Javan Rhino" (On-line). Accessed October 13, 1999 at http://www.rhinos-irf.org/rhinos/javan.html.

"Javan Rhinoceros" (On-line). Accessed October 13, 1999 at http://www.panda.org/resources/publicati...ies/threatened/JavanRhinoceros.

O'Conner, A. July 20, 1999. Thought Extinct, a Few Rhinos Are Seen in Vietnam. The New York Times.

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