Rhinoceros sondaicus

Geographic Range

The Javan rhino, Rhinoceros sondaicus , is also known as the lesser-one horned rhino. The historical range of the Javan rhino is believed to have included southeastern areas of Asia. In the past, the Javan rhino ranged from the highest northern parts of Burma and quite possibly extended to present-day eastern Vietnam. However, it is known that the Javan species also inhabited all areas of Sumatra. It was also found in the north and northeastern region of Thailand, extending into Cambodia. It is possible that the rhino's range included the southern Malaysian peninsula. The rhino once inhabited the majority of the Javan island.

Today, its only known location is in the Udjong Kulon Nature Reserve, located in the furthest southwestern areas of Java, where some 50 individuals remain. There is also a small (less than 10 individuals) population in the Cat Tien National Park in Viet Nam.

• Biogeographic Regions
• oriental oriental
  • native native

Habitat

Javan rhinos are most commonly found in tropical forests that are generally close to sea level. Rhinoceros sondaicus thrives in the lowland, grassy fields close to a water source where it typically spends most of the day wallowing.

This lowland species may be found at elevations up to 1000m, but it's much more common below 600m.

• Habitat Regions
• tropical tropical

• Terrestrial Biomes
• forest forest

• Other Habitat Features
• riparian riparian

Physical Description

Rhinoceros sondaicus is also known as the lesser one-horned rhinoceros, as its horn is smaller than any of the other rhino species. Mature males have only one horn that is 25 cm long, while females lack a horn entirely. The horn has no attachment to the bone structures of the skull. The Javan rhino has a grey hide with multiple rigid folds that come together to form sectionalized creases.

Unlike Rhinoceros unicornis (Indian rhinoceros), the Javan rhino has a dorsal crease rather than one originating from the neck. The folds of the Javan rhino are present on the shoulder, the back, and the hind end. The horn shares the same color of the hide.

Rhinoceros sondaicus averages about 1.7m at the shoulder. Its length may vary between 2.0-4 m. Males and females have a similar average body mass. However, some measurements of heads indicate that females are larger. The body mass of both sexes can range from 1500-2000 kg.

Despite being virtually hairless, the Javan rhino does have sparse hairs around the nose and horn. The 70-cm tail has a patch of hair at the end.

As a forager, the rhino has developed an elongated upper lip that extends out and over the bottom lip. Is has large incisor teeth; however, no information on the description of the incisors has been published.

Much of the historical information about physical description on the rhino is questionable as it had been mistaken for the Sumatran rhinoceros, Dicerorhinus sumatrensis through the late 1800's.

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger
• ornamentation ornamentation

Reproduction

Mating behavior in Rhinoceros sondaicus has only been observed on a few accounts, but it is thought to be polygynandrous. Male and female Javan rhinos fight and produce loud roars, presumably a type of courtship. One pairs had been observed tearing up vegetation together, followed by a pursuit of over 200m.

Other species of rhinos like the Indian rhino ( Rhinoceros unicornis ) have extensive ritualized behaviors prior to copulation, occasionally resulting in serious injury.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Male rhinos will "whistle" to attract females in the area; typically the loudest whistle is associated with the most dominant male.

Javan rhinos breed year-round, producing one calf at a time. The calf is weaned within 1-2 years. The breeding interval is once every 4-5 years, due to a 16-month gestation period and a lengthy period of mother-calf interaction.

Rhinos of this species attain sexual maturity as early as 5-7 years of age for females, and 10 years of age in males.

Only anecdotal information is available regarding growth and rate of maturity. In one case, a fetus was noted to be 17cm and presumed to be halfway through gestation. In a second case, a young rhino, in which the age was not specified, was 130cm in length. It was fully grown by the age of 4 and had reached 170cm in length.

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

A cow will stay with the calf for up to two years post-partum. The calf feeds from the mother shortly after walking is achieved, which is 1-2 hours after birth. The bull has no parental investment beyond mating.

• Parental Investment
• female parental care female parental care
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • female

Lifespan/Longevity

Records on the longevity of Rhinoceros sondaicus do not exist. It is predicted that they could reach 30-40 years of age in the wild. A specific captive rhino lived to 21 years and died in 1907. The species is known for its lower lifespan when placed in captivity. A pair of rhinos kept at a London zoo only lived to 11 and 14. The expected lifespan in captivity is about 10-20 years.

Behavior

Rhinoceros sondaicus is generally solitary. The majority of is spent wallowing in order to keep its hide moisturized. Inhibition of wallowing may result in possible bacterial and disease issues.

Researcher Yahya found no difference in wallowing behavior between the sexes. While wallowing, the rhino will stand or sit. The Javan rhino will roll in the mud and rub its horn into the sediment, generally understood as an attempt to deepen the watering hole. The horn helps protect the rhino in dense brush areas. The rhino will also sleep while wallowing.

Javan rhinos will perform various bouts that are not seen to be used for communication. Rubbing their horn against a solid surface (like a tree), shaking their head, and moving their ears are typical gestures. The Javan rhino uses many aggressive behaviors, like attacking and/or charging a threat. The rhinos will also concentrate on a supposed threat and not move to indicate their refusal to step back and give up their ground. This aggressive behavior is generally seen in the bulls, accompanied by loud roaring.

There are some behaviors in the rhino solely categorized by interactions between a cow and her calf. If a threat arises, the cow will stand in between the threat and her calf in an offensive manner. In other instances, a cow was seen rushing toward her young when a supposed threat was detected.

• Key Behaviors
• terricolous
• natatorial natatorial
• motile motile
• solitary solitary

Home Range

Javan rhinos may travel up 20 km in a span of one day, browsing for suitable food items.

The predicted size of the home range for a female is a maximum of 500 ha or 5 square km. It's suspected that male home ranges are even larger. For example, a single male was recorded using an area of 100 square kilometers.

The Javan rhino does not defend a specific territory. Males will secrete a orange-red urine onto vegetation around the area they are occupying.

Population density is low in the Udjong Kulon Park at 0.30 rhinos per square kilometer. In this park, individuals move 0.4-3.8 km per day. Females overlap often while males rarely overlap, especially those that have made a clear defined trail.

Communication and Perception

Rhinoceros sondaicus does not have strong visual perception. Therefore, it predominately uses its sense of smell and hearing.

The Javan rhino communicates via chemical methods by spreading bodily secretions throughout the environment to display dominance or protection of territory. Such secretions include defecating on or nearby another Javan rhino's previous defacating site, most likely done more by dominant males. The Javan rhinos are also found to relieve their bowels in some form of water the majority of the time. It is also frequently done in wallows.

The Javan rhino is able to produce an array of sounds that have a distinct meaning. The various acoustics produced by the Javan rhino include a "neigh," a "bleat," a "shriek," "lip vibrations" and a "snort" (Groves and Leslie Jr., 2011). There are some accounts of loud growling that can be heard >600m away.

Generally solitary, it will interact while attracting mates by displays of fighting. The mother of a newborn will stay with its calf for over two years.

• Communication Channels
• visual visual
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• scent marks scent marks
• vibrations vibrations

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• vibrations vibrations
• chemical chemical

Food Habits

Rhinoceros sondaicus is an herbivore, but does not eat grasses. While the Javan rhino can eat bamboo and some plants with sharp structures, this rhino will preferably consume softer vegetation such as some figs Ficus variegata and guest tree Kleinhovia variegata .

This rhino may resort to extreme methods to access food. Some have been seen bending taller plants to reach the desired food. There are some accounts of the rhinos saddling themselves on a tree's base and then working their way to the top until the tree is bent and the vegetation is accessible.

Low and tropical forested areas have a higher density of toxic plants and the Javan rhinoceros is able to ingest certain kinds of toxic plants in large quantities.

• Primary Diet
• herbivore herbivore
  • folivore folivore
  • frugivore frugivore
  • lignivore

• Plant Foods
• leaves
• wood, bark, or stems
• fruit

Predation

Aside human destruction of habitat and illegal poaching, there are no known predators of Javan rhinos. The now extinct Javan tiger ( Panthera tigris sondaica ) was capable of killing a stranded calf less than six months old.

Ecosystem Roles

Due to the rarity of the Javan rhino, it is no longer sympatric with the banteng, Bos javanicus , as well as the Sumatran rhino Dicerorhinus sumatrensis . The Javan rhino was once competitive with these species. The Javan tiger, Panthera tigris , once preyed on the young of Javan rhinos.

Parasitic organisms have been detected in the feces of Rhinoceros sondaicus . Organisms in the Amblyomma (ticks) and Tabanus (roundworms) genera have been found in and on the Javan rhino.

Rhinoceros sondaicus will typically affect the environment by laying trails by stomping and breaking vegetation.

Economic Importance for Humans: Positive

The horn of the Javan rhino has been greatly sought after in many cultures. The horns of Asian rhino species are worth up to 10 times their African counterparts. The horns are used for medical purposes in Chinese remedies as a fever reducer. Other non-legitimate purposes include snake bite cures, Indian aphrodisiacs and a natural detector of poisonous substances. It is believed that the reaction occurring from poisonous substances is from the high concentration of calcium. However, no real medical values have ever been confirmed.

• Positive Impacts
• body parts are source of valuable material
• source of medicine or drug source of medicine or drug

Economic Importance for Humans: Negative

There are no negative effects by Rhinoceros sondaicus on human populations.

Conservation Status

The IUCN Redlist placed the Javan rhino as critically endangered in 2008. With only 60 individuals in the Ujong Kulon National Park, less than 10 in Viet Nam, and none in captivity, the Javan rhino faces extinction without the necessary conservation. This makes the Javan rhino the rarest rhino species, behind the Sumatran rhino, Dicerorhinus sumatrensis . The last captive Javan rhino died in 1907. None are kept in captivity due to the Javan rhino's diminished lifespan in zoo environs.

In the early 1800's extensive poaching and habitat loss began in most of the areas inhabited by Rhinoceros sondaicus . There are some biological influences that threaten this population, like a few seismic volcanoes in Java that could potentially wipe out the species in the event of an eruption.

The Asian Rhino Specialist Group has established a plan of action to increase the population. This plan includes relocating a few individuals to a new breeding area. However, natural reproduction has not been documented in the existing population in Viet Nam; it's been suggested that the remaining individuals (perhaps just 6) are either all the same sex or too old to breed.

More planning is needed before real actions are taken.

CITES lists the Javan rhino under appendix I. All species in this category are considered to be threatened with possible extinction. Import and export of any part of this species is generally not allowed. Commercial use of the species is forbidden.

The Federal Endangered Species List listed the Javan rhino as endangered before the Endangered Species Act was passed. The Federal Register recognizes that the species is endangered under the list of Endangered Foreign Species. However, Rhinoceros sondaicus does not actually appear on the Federal list.

Additional Links

Encyclopedia of Life

Contributors

Matt Crider (author), Radford University, Karen Powers (editor), Radford University, April Tingle (editor), Radford University, Emily Clark (editor), Radford University, Cari Mcgregor (editor), Radford University, Jacob Vaught (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

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