Javan rhinoceros

The generic name Rhinoceros is a combination of the ancient Greek words ῥίς (ris) meaning nose and κέρας (keras) meaning horn of an animal. The specific name sondaicus is derived from sunda, the biogeographical region that comprises the islands of Sumatra, Java, Borneo, and surrounding smaller islands. The Javan rhino is also known as the lesser one-horned rhinoceros (in contrast with the greater one-horned rhinoceros, another name for the Indian rhino). == Taxonomy ==

Rhinoceros sondaicus was the scientific name used by Anselme Gaëtan Desmarest in 1822 for a rhinoceros from Java sent by Pierre-Médard Diard and Alfred Duvaucel to the National Museum of Natural History, France. In the 19th century, several zoological specimens of hornless rhinoceroses were described: • Rhinoceros inermis proposed by René Lesson in 1838 was a female rhinoceros without horns shot in the Sundarbans. • Rhinoceros nasalis and Rhinoceros floweri proposed by John Edward Gray in 1867 were two rhinoceros skulls from Borneo and one from Sumatra, respectively. • Rhinoceros annamiticus proposed by Pierre Marie Heude in 1892 was a specimen from Vietnam. As of 2005, three Javan rhinoceros subspecies are considered valid taxa: The extant family, the Rhinocerotidae, first appeared in the Late Eocene in Eurasia, and the ancestors of the extant rhino species dispersed from Asia beginning in the Miocene. The last common ancestor of living rhinoceroses belonging to the subfamily Rhinocerotinae is suggested to have lived around 16 Mya, with the ancestors of the genus Rhinoceros diverging from the ancestors of other living rhinoceroses around 15 Mya. The genus Rhinoceros has been found to be overall slightly more closely related to the Sumatran rhinoceros (as well as to the extinct woolly rhinoceros and the extinct Eurasian genus Stephanorhinus) than to living African rhinoceroses, though gene flow appears to have occurred between the ancestors of living African rhinoceroses and the genus Rhinoceros, as well as between the ancestors of the genus Rhinoceros and the ancestors of the woolly rhinoceros and Stephanorhinus. A cladogram showing the relationships of recent and Late Pleistocene rhinoceros species (minus Stephanorhinus hemitoechus) based on whole nuclear genomes Molecular estimates suggest the Indian and Javan rhinoceros diverged from each other earlier, around 4.3 million years ago. == Description ==

Javan rhinos are smaller than the Indian rhinoceros, and are close in size to the black rhinoceros. They are the largest animal in Java and the second-largest animal in Indonesia after the Asian elephant. The length of a Javan rhino including its head is , and it can reach a height of . Adults are variously reported to weigh between , although a study to collect accurate measurements of the animals has never been conducted and is not a priority because of their extreme conservation status. No substantial size difference is seen between genders, but cows may be slightly bigger. The rhinos in Vietnam appeared to be significantly smaller than those in Java, based on studies of photographic evidence and measurements of their footprints. Like the Indian rhino, the Javan rhino has a single horn (the other extant species have two horns). Its horn is the smallest of all extant rhinos, usually less than with the longest recorded only . Only bulls have horns. Cows are the only extant rhinos that remain hornless into adulthood, though they may develop a tiny bump of an inch or two in height. Javan rhinos do not appear to often use their horns for fighting, but instead use them to scrape mud away in wallows, to pull down plants for eating, and to open paths through thick vegetation. Similar to the other browsing species of rhino (black and Sumatran), the Javan rhino has a long, pointed, upper lip, which helps in grabbing food. The lower incisors are long and sharp; when Javan rhinos fight, they use these teeth. Behind the incisors, two rows of six low-crowned molars are used for chewing coarse plants. Like all rhinos, Javan rhinos smell and hear well, but have very poor vision. They are estimated to live for 30 to 45 years. Their hairless, splotchy gray, or gray-brown skin falls in folds to the shoulder, back, and rump. The skin has a natural mosaic pattern, which lends the rhino an armored appearance. The neck folds of Javan rhinoceros are smaller than those of the Indian rhinoceros, but still form a saddle shape over the shoulders. Because of the risks of interfering with such an endangered species, however, Javan rhinos are primarily studied through fecal sampling and camera traps. They are rarely encountered, observed, or measured directly. == Distribution and habitat ==

is the home of all remaining Javan rhinos. Fossil remains of Javan rhinoceros have been found at the Neolithic site of Hemudu in Zhejiang, China, and the 4th century BCE Classic of Mountains and Seas appears to describe one living in the Yangtze River basin. Remains were also found in the Tam Hay Marklot cave site in northeastern Laos that date to the Pleistocene. Historically, Javan rhinoceroses were widespread from Assam and Bengal, Today, the species only occurs in Ujung Kulon National Park in southwestern Java, where fewer than 100 individuals are estimated to survive. By the end of the Vietnam War, the Vietnamese rhinoceros was thought extinct across all of mainland Asia. Local hunters and woodcutters in Cambodia claim to have seen Javan rhinos in the Cardamom Mountains, but surveys of the area have failed to find any evidence. The population in Vietnam's Cat Tien National Park was declared locally extinct in 2011. The Javan rhinoceros primarily inhabits dense, lowland rain forests, grasslands, and reed beds with abundant rivers, large floodplains, or wet areas with many mud wallows. Although it historically preferred low-lying areas, the subspecies in Vietnam was pushed onto much higher ground (up to 2,000 m or 6,561 ft), probably because of human encroachment and poaching. == Behavior ==

The Javan rhinoceros is a solitary animal with the exception of breeding pairs and mothers with calves. They sometimes congregate in small groups at salt licks and mud wallows. Wallowing in mud is a common behavior for all rhinos; the activity allows them to maintain cool body temperatures and helps prevent disease and parasite infestation. The Javan rhinoceros does not generally dig its own mud wallows, preferring to use other animals' wallows or naturally occurring pits, which it uses its horn to enlarge. Salt licks are also very important because of the essential nutrients the rhino receives from the salt. Bull home ranges are larger at compared to the cow, which are around . Bull territories overlap each other less than those of the cow. Whether territorial fights occur is unknown. The Javan rhino is much less vocal than the Sumatran; very few Javan rhino vocalizations have ever been recorded. Adults have no known predators other than humans. The species, particularly in Vietnam, is skittish and retreats into dense forests whenever humans are near. Though a valuable trait from a survival standpoint, it has made the rhinos difficult to study. Nevertheless, when humans approach too closely, the Javan rhino becomes aggressive and will attack, stabbing with the incisors of its lower jaw while thrusting upward with its head. Its comparatively antisocial behavior may be a recent adaptation to population stresses; historical evidence suggests they, like other rhinos, were once more gregarious. Diet The Javan rhinoceros is herbivorous, eating diverse plant species, especially shoots, twigs, young foliage, and fallen fruit. Most of the plants favored by the species grow in sunny areas in forest clearings, shrubland, and other vegetation types with no large trees. The rhino knocks down saplings to reach its food and grabs it with its prehensile upper lip. It is the most adaptable feeder of all the rhino species. Currently, it is a pure browser, but probably once both browsed and grazed in its historical range. The rhino eats an estimated of food daily. Like the Sumatran rhino, it needs salt in its diet. The salt licks common in its historical range do not exist in Ujung Kulon, but the rhinos there have been observed drinking seawater, likely for the same nutritional need. == Conservation ==

The main factor in the continued decline of the Javan rhinoceros population has been poaching for horns, a problem that affects all rhino species. The horns have been a traded commodity for more than 2,000 years in China, where they are believed to have healing properties. Historically, the rhinoceros' hide was used to make armor for Chinese soldiers, and some local tribes in Vietnam believed the hide could be used to make an antidote for snake venom. In May 2017, Director of the Biodiversity Conservation at the Ministry of Environment and Forestry, Bambang Dahono Adji announced plans to transfer the rhinos to the Cikepuh Wildlife Sanctuary located in West Java. The animals will first undergo DNA tests to determine lineage and risk to disease so as to avoid issues such as inbreeding or marriage kinship. As of December 2018, these plans had yet to happen. In December 2018, the remaining Javan rhino population was severely endangered by the tsunami triggered by nearby volcano Anak Krakatau. At least four Javan rhinoceros calves have been recorded between August 2023 and 2024; one seen in May 2024 was estimated to have been three to five months old. Cat Tien Once widespread in Southeast Asia, the Javan rhinoceros was presumed extinct in Vietnam in the mid-1970s, at the end of the Vietnam War. The combat wrought havoc on the ecosystems of the region through the use of napalm, extensive defoliation from Agent Orange, aerial bombing, use of landmines, and overhunting by local poachers. ==In culture==

The Javan rhinoceros occurred in Cambodia in the past and at least three depictions of rhinos are in the bas reliefs of the temple at Angkor Wat. The west wing of the North Gallery has a relief that shows a rhino mounted by a god thought to be the fire god Agni. The rhinos are thought to be Javan rhinoceros rather than the somewhat similar-looking one-horned Indian rhino on the basis of the skinfold on the shoulder that continues along the back in the Javan to give a saddle-like appearance. A depiction of the rhino in the east wing of the South Gallery shows a rhino attacking the damned in the panel depicting heaven and hell. An architect of the temple is thought to have been an Indian Brahmin priest named Divakarapandita (1040–1120 AD) who served king Jayavarman VI, Dharanindravarman I, as well as Suryavarman II, who constructed the temple. The Indian priest who died before the construction of the temple is thought to have influenced the use of tubercles on the skin, which are based on the Indian rhino, while the local Khmer artisans carved the other details of the rhinos based on the more familiar local Javan rhino. The association of the rhinoceros as the vahana of the god Agni is unique to Khmer culture. Another rhinoceros carving in the middle of a circular arrangement in a column with other circles containing elephants and water buffalo is known from the temple of Ta Prohm. Based on anachronistic speculation, it might represent a stegosaur due to the leaves behind it that give the impression of plates. The mascot of the 2023 FIFA U-20 World Cup is a Javan rhinoceros named Bacuya. == References ==