Javan Rhinoceros, Rhinoceros sondaicus
The Javan rhinoceros (Rhinoceros sondaicus), also known as the Sunda rhinoceros or the lesser one-horned rhinoceros, is one of five living species of rhino that can be found in a small area in western Java in Ujung Kulon National Park. Its range once extended from Bengal and Assam to Cambodia, Thailand, Myanmar, Vietnam, and Laos and included the islands of Sumatra and Java. This species prefers to reside in grasslands, rainforests, and reed beds with abundant vegetation and water at higher elevations, although it once preferred lower elevations.
The Javan rhinoceros first become known to naturalists outside of its range in 1787, when Petrus Camper and Alfred Duvaucel shot specimens to study them. Duvaucal sent the specimens to Georges Cuvier, who classified it as a distinct species in 1822. It was given its scientific name that same year and was the last rhinoceros to be discovered. This species holds three recognized subspecies, including the Indonesian Javan rhinoceros, which is its only remaining subspecies.
The Javan Rhinoceros reaches an average body length of up to 13 feet, with a height of up to 5.8 feet and a weight between 2,000 and 5,100 pounds. This species is hairless and has spotted greyish brown to grey skin that holds a mosaic-like pattern, which makes it look armored. The skin folds along the neck, shoulders, and back, although its folds are not as prominent as those of the Indian rhinoceros. This species holds a short horn that can reach 7.9 inches in length. It is not thought to use this horn to fight, but will use it to pull vegetation down to eat, to move mud, and to create paths in thick foliage. As is typical to rhino species, this rhino has poor eyesight, but is skilled in smelling and hearing.
Although this species may gather in small groups around water holes or salt licks, it is primarily a solitary species. Males hold home ranges that can reach eight miles in length, while females hold smaller home ranges that reach up to five miles. The home ranges of females overlap those of males and other females. Males mark their territories by urinating and defecating, but it is not known whether males fight strange males within the territories.
The Javan rhinoceros is not known to make a large range of vocalizations and few have been recorded. When approached by humans, this species either runs away or attacks with its sharp lower incisors, behaviors that are thought to be recent adaptations to defend a dwindling population. It has no known natural predators, although humans have hunted it to near extinction. Like other rhinoceroses, this species is an herbivore. It consumes young leaves, fallen fruit, twigs, and other plant materials. Most of its preferred food types occur in sunny or clear areas with little tree coverage. It will use its horn to break down saplings and consume the leaves by using its prehensile upper lip. This species is known to require salt in its diet and has been seen drinking sea water in areas where natural salt licks are not present.
The main threat that has affected the Javan rhinoceros has been poaching by humans, who have killed so many rhinos that many species are in danger of extinction. Despite education of locals and those interested in buying rhino horns, this species was still hunted and sold for large sums of money. It was granted full protection from the Convention on International Trade in Endangered Species of Wild Fauna and Flora, making any trade of this species and its horns illegal. Habitat destruction is also thought to be a major threat to this species and it has been forced to adapt to new habitats due to human encroachment. Although conservation efforts have been enacted for this species and it resides in protected area, it is unknown whether this species can survive. A small population number, estimated at less than forty individuals, has caused inbreeding and a susceptibility to disease, which also threatens it. Currently, the Javan rhinoceros appears on the IUCN Red List with a conservation status of “Critically Endangered.”
Image Caption: Javan Rhino (Rhinoceros sondaicus sondaicus) shown in the London Zoo from march 1874 until january 1885. Credit: T.Dixon/Wikipedia