JAVAN RHINOCEROS: CHARACTERISTICS, BEHAVIOR, UJUNG KULON

JAVAN RHINOCEROS

The Javan rhinoceros is slightly smaller than the Indian rhino and a little bit larger than the Sumatran rhino. Like the closely related Indian rhinoceros, the Javan rhinoceros has a single horn. Its distinguishing features are its 26-centimeters horn and a prominent fold in the hide of its front shoulder. More than almost any other creature living today it resembles the prehistoric mammals which dominated the earth millions of years ago. [Source: Diter and Mary Plage, National Geographic, June 1985]

The Javan rhino is one of the rarest large mammal on Earth. There are only around 76 of the animals left in existence, all living in the wild in Ujung Kulon National Park. There are none in captivity. They used to be the rarest rhino but now that grim distinction goes to the Sumatran rhino, of which only 35 to 50 are thought to exist in the wild (plus a few at zoos and sanctuaries). According to Indonesia's environment ministry there are only 72 Javan rhinos — 39 males and 33 females — left in the wild in 2020. [Source: Reuters, July 2, 2020]

Reporting from Ujung Kulon, Arlina Arshad of AFP wrote: “The shy creature, whose folds of loose skin give it the appearance of wearing armour plating, once numbered in the thousands and roamed across Southeast Asia. Officials in Ujung Kulon believe there were 51 of the rhinos in 2012, including eight calves, basing their estimate on images captured by hidden cameras. They hope the true figure may be in the 70s and will have a new estimate once data for 2013 has been collated. [Source: Arlina Arshad, AFP, December 23, 2013]

Of all the rhino species, the least is known of the Javan Rhino. These animals prefer dense lowland rain forest, tall grass and reed beds that are plentiful with large floodplains and mud wallows. Javanese rhinos are very shy. They will flee their normal browsing grounds if they sense humans or animals such as oxen or deer coming near. Females give birth and raise their calves near the coast. The gestation period is 16 months. One calf is born and it is thought to saty with the mother for around two years. Sections of males home ranges usually extend to the coast. They are thought to be territorial, marking their territory with piles of dung and urine pools.

The genus Rhinoceros is a classification for the the Javan rhinoceros (Rhinoceros sondaicus) and Indian rhinoceros (Rhinoceros unicornis). The scientific name for the genus Rhinoceros was established by Linnaeus in 1758. Rhinoceros is the only genus in Rhinocerotidae to possess one horn, incisors, and lower canines. The Javan and Indian rhinoceros are very similar in appearance but the Indian rhinoceroses are much larger in size, with individual Indian rhinoceroses weighing up 3000 kilograms. [Source: Evan Smith, Animal Diversity Web (ADW) /=]

Websites and Resources on Animals: International Rhino Foundation rhinos.org ; Save the Rhino International savetherhino.org; Animal Diversity Web animaldiversity.org ; BBC Earth bbcearth.com; A-Z-Animals.com a-z-animals.com; Live Science Animals livescience.com; Animal Info animalinfo.org ; World Wildlife Fund (WWF) worldwildlife.org the world’s largest independent conservation body; National Geographic National Geographic ; Endangered Animals (IUCN Red List of Threatened Species) iucnredlist.org

Range and Habitat of the Javan Rhinoceroses

Javan rhino range

Javan rhinoceroses(Rhinoceros sondaicus_ currently occupies a single national park, Ujong Kulong, in the furthest southwestern areas of Java, Indonesia, where some 50 individuals remain. Javan rhinoceroses are thought to have been the most widespread species in Rhinocerotidae, ranging from India to Vietnam, and throughout Sumatra and Borneo, until its recent decline. They were also found in the north and northeastern region of Myanmar and 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. One individual was found in the Cat Tien National Park in Viet Nam in the 2000s. [Source: Evan Smith, Animal Diversity Web (ADW) /=]

The Javan rhino is also known as the lesser-one horned rhino. They are most commonly found in tropical forests that are generally close to sea level, and thrives in the lowland, grassy fields close to a water source where it typically spends most of the day wallowing. They have been found at elevations up to meters (3281 (high) feet) but are generally found at elevations less than 600 meters (1968 feet). [Source: Matt Crider, Animal Diversity Web (ADW) /=]

According to Animal Diversity Web: Rhinoceros species occupy tropical ecosystems. They prefer having a source of water nearby, to create features such as muddy riverbanks, or mud pits to wallow in during the heat of the day. Javan rhinoceroses occupies the lowland tropical rainforest of West Java, but historically occurred in a variety of habitats including mixed forests, grasslands, and even rugged mountainous areas. Not much is known about their preferred habitat since only a single population remains. The species is thought to be a browser, preferring all things woody, and eating very little grass./=\

Javan Rhinoceros Characteristics

The Javan rhinoceros’s hairless, hazy gray skin falls into folds into the shoulder, back, and rump giving it an armored-like appearance. The Javan rhino's body length reaches up 3.2 meters (10 feet), including its head and stands 1.5 to 1.7 meters (4 feet, 10 inches to 5 feet 7 inches) at the shoulder. Adults are variously reported to weigh between 900 to 1,400 kilograms or 1,360 to 2,000 kilograms. Only males have true horns. Females have knobs or nothing that is visible.

Javan rhinoceros are relatively hairless except for their ears. The thick gray skin is divided into deep folds, making a saddle over the neck, with lumps or nodules, giving an armor-plated effect. The horn is relatively short.

Javan rhinoceroses range in weight from 1500 to 2000 kilograms (3304 to 4405 pounds) and range in length from two to four meters (6.5 to 13 feet) and stand on average about 1.7 meters at the shoulder. Sexual Dimorphism (differences between males and females) is present: Females are larger than males. Males and females have a similar average weight body mass, however some measurements of heads indicate that females are larger. Ornamentation is a little different. Females possess either no horn or or just a small knob.[Source: Matt Crider, Animal Diversity Web (ADW) /=]

rhino sizes

The Javan rhinoceroses is sometimes called the lesser one-horned rhinoceros because its horn is smaller than any of the other rhino species. Mature males have only one horn that is 25 centimeters long, while females lack a horn entirely. The horn has no attachment to the bone structures of the skull. The horn is roughly the same color as the hide. It helps protect the rhino in dense brush areas.

Javan rhinos have a grey hide with multiple rigid folds that come together to form sectionalized creases. Unlike the 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. Despite being virtually hairless, Javan rhinos do have sparse hairs around the nose and horn. The 70-centimeter tail has a patch of hair at the end. /=\

Records on the longevity of Javan rhinoceroses 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. /=\

Javan Rhinoceros Food and Eating Behavior

Javan rhinoceroses are herbivores (primarily eat plants or plants parts) but also qualify as folivores (eat leaves), frugivores (eat fruits), lignivore (eat wood). Among the plant foods they eat are leaves, wood, bark, or stems fruit. Although Javan rhinoceroses are herbivores, they do not eat grasses. They can eat bamboo and some plants with sharp structures but they prefer softer vegetation such as some figs Ficus variegata and guest tree Kleinhovia variegata.[Source: Matt Crider, Animal Diversity Web (ADW) /=]

Matt Crider wrote in Animal Diversity Web: Javan rhinoceroses 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 rhinoceroses is able to ingest certain kinds of toxic plants in large quantities. /=\

Asian Rhinoceros species are generalist browsers with a prehensile upper lip. Their prehensile upper lip allows them to grasp woody branches and pull them into their mouth. Indian rhinoceroses eats grass, woody twigs and branches, and semi-aquatic plants. Javan rhinoceroses eats strictly vegetation from woody plants, or leaves, twigs, and branches. /=\

Javan Rhinoceros Behavior

Javan rhinoceros species are terricolous (live on the ground), diurnal (active during the daytime), natatorial (equipped for swimming), motile (move around as opposed to being stationary) and solitary. The majority of their time is spent wallowing in order to keep its hide moisturized and possibly to help with bacterial and disease problems. Researcher Yahya found no difference in wallowing behavior between the sexes. While wallowing, the rhinos stand or sit. They sometimes roll in the mud and rub their horn into the sediment of their wallow. It is generally believed they do this to deepen the wallow. The rhino will also sleep while wallowing. [Source: Matt Crider, Animal Diversity Web (ADW) /=]

Largely nocturnal, Javan rhinos it eats a variety of plant but seem to prefer the shoots of young trees. If they can't reach the shoots on small trees they will often knock the tree down to get at them. The presence of rhino tracks on the beach led some scientists to speculate that the rhinos also eat salt-water mangroves.

Javan rhinos may travel up 20 kilometers in one day, browsing for suitable food items. Males have large territories, with only a single male occupying each range. The predicted size of the home range for a female is a maximum of 500 hectares (five square kilometers). 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 secrete a orange-red urine onto vegetation around the area they are occupying. Population densities in the Udjong Kulon Park are low: 0.30 rhinos per square kilometer, with individuals moving 0.4-3.8 kilometers per day. Females overlap often while males rarely overlap, especially those that have made a clear defined trail.

Generally solitary, Javan rhinoceroses generally only interact when breeding, sometimess with displays of fighting. The mother of a newborn will stay with its calf for over two years. According to Animal Diversity Web: Groups will only be seen during mating, a mother and calf, and small groups of adolescent males. Rhinoceros males occupy a territory, with females moving freely about. Indian rhinoceroses males have constantly changing territories depending on the season with possible overlap of territories with other males, and will defend their territory aggressively from other males.[Source: Evan Smith, Animal Diversity Web (ADW) /=]

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. /=\

Javan Rhinoceros Senses and Communication

Javan rhinoceroses sense using vision, touch, sound, vibrations and chemicals usually detcted with smell and communicate with vision, sound and chemicals usually detected by smelling and scent marks (produced by special glands and placed so others can smell or taste them) and vibrations. [Source: Matt Crider, Animal Diversity Web (ADW) /=]

Javan rhinoceroses do not have very good eyesight. They rely primarily on their sense of smell and hearing. They much less vocal, with only five vocalizations, than Indian rhinoceroses. The Some of their sounds are believed to have distinct meanings. Among these are "neighs," "bleats," "shrieks," "lip vibrations" and "snorts". There are some accounts of loud growling that can be heard more than 600 meters away. /=\

Rhinoceroses often communicate with others mainly through scents. Javan rhinoceroses leaves dung heaps to mark its territory, as well as a substance it projects from snorting to create scent markers. According to Animal Diversity Web: Javan rhinos 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. Javan rhinoceroses leaves dung heaps to mark its territory, as well as a substance it projects from snorting to create scent markers.

Javan Rhinoceros Mating, Reproduction and Offspring

Javan rhinoceroses engage in year-round breeding about once every four to five years due to a 16-month gestation period and a lengthy period of mother-calf nursing. The number of offspring is usually one. Mating behavior in Javan rhinoceroses have only been observed on a few accounts, but it is thought they are polygynandrous (promiscuous), with both males and females having multiple partners. [Source: Matt Crider, Animal Diversity Web (ADW) /=]

Male rhinos will "whistle" to attract females in the area; typically the loudest whistle is associated with the most dominant male. 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 200 meters. Other species of rhinos like the Indian rhino have extensive ritualized behaviors prior to copulation, occasionally resulting in serious injury.

The average gestation period for Javan rhinoceroses is 16 months. The age in which they are weaned ranges from 12 to 24 months and the average time to independence is two years. Females reach sexual or reproductive maturity at five to seven years. On average males reach sexual or reproductive maturity at 10 years. 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 beyond mating. /=\

Parental care and pre-birth, pre-weaning and pre-independence provisioning and protecting are all done by females. Only anecdotal information is available regarding growth and rate of maturity. In one case, a fetus was noted to be 17 centimeters and presumed to be halfway through gestation. In a second case, a young rhino, in which the age was not specified, was 130 centimeters in length. It was fully grown by the age of four and had reached 170 centimeters in length. /=\

Image Sources: Wikimedia Commons

Text Sources: Animal Diversity Web animaldiversity.org ; National Geographic, Live Science, Natural History magazine, David Attenborough books, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Discover magazine, The New Yorker, Time, Reuters, Associated Press, AFP, Lonely Planet Guides, Wikipedia, The Guardian, Top Secret Animal Attack Files website and various books and other publications.

Last updated December 2024