The Javan rhinoceros (Rhinoceros sondaicus), also called the Javan rhino, Sunda rhinoceros, and lesser one-horned rhinoceros, is a critically endangered animal in the rhinoceros family (Rhinocerotidae). It is one of five living rhinoceros species. This rhino has thick, folded skin for protection and is one of the smallest rhinoceros species. It measures about 3.1–3.2 meters (10.2–10.5 feet) in body length and has a tail that is 1.4–1.7 meters (4.6–5.6 feet) long. The heaviest Javan rhinos weigh around 2,300 kilograms (5,100 pounds). Their horns are usually less than 25 centimeters (9.8 inches) long.

Until the mid-1800s to early 1900s, Javan rhinos lived in areas beyond Java and Sumatra, including parts of Southeast Asia, Indochina, East India, Bhutan, and southern China. Today, they are the rarest rhinoceroses and among the rarest living animals. Only one wild population exists, and no Javan rhinos have been successfully kept in captivity. This population lives in Ujung Kulon National Park, at the western tip of Java, Indonesia, with about 74 individuals.

The Javan rhino’s population has declined mainly because of poaching. Their horns are highly valued in traditional Chinese medicine and can cost up to US$30,000 per kilogram on the black market. During the 1700s and 1800s, European settlers increased in the region, leading to trophy hunting. Loss of habitat and rapid human population growth, especially after World War II, have also harmed the species. The remaining Javan rhinos live in a protected area, Ujung Kulon National Park, which is a UNESCO World Heritage Site. However, the park’s remote and rugged boundaries make it difficult for law enforcement to protect all areas equally. This lack of security puts the rhinos at risk from poachers, disease, and genetic problems caused by inbreeding.

Javan rhinos can live about 30–45 years in the wild. They once lived in dense lowland rainforests, wet grasslands, and floodplains near forests. They are mostly solitary, except during mating or when raising young. They may gather near muddy areas or salt licks. Adults avoid humans and have no natural predators in their range. Very young rhinos may be hunted by leopards, Sumatran tigers, or rarely, saltwater crocodiles. Scientists rarely study Javan rhinos directly because they are so rare and endangered. Instead, researchers use camera traps and animal droppings to learn about their health and behavior.

In 2011, scientists recorded footage of two adult female Javan rhinos with their calves using a motion-triggered camera. This video, released by WWF and Indonesia’s National Park Authority, showed that Javan rhinos are still breeding in the wild.

Etymology

The name Rhinoceros comes from two ancient Greek words: ῥίς (ris), which means "nose," and κέρας (keras), which means "horn of an animal." The specific name sondaicus comes from the word "sunda," which refers to a region that includes the islands of Sumatra, Java, Borneo, and smaller nearby islands. The Javan rhino is also called the lesser one-horned rhinoceros. This name contrasts with the greater one-horned rhinoceros, which is another name for the Indian rhino.

Taxonomy

In 1822, Anselme Gaëtan Desmarest gave the scientific name Rhinoceros sondaicus to a rhinoceros from Java that was sent to the National Museum of Natural History in France by Pierre-Médard Diard and Alfred Duvaucel. During the 19th century, several hornless rhinoceros species were described based on specimens:

• In 1838, René Lesson named Rhinoceros inermis for a female rhinoceros without horns found in the Sundarbans.
• In 1867, John Edward Gray named Rhinoceros nasalis and Rhinoceros floweri for two rhinoceros skulls from Borneo and one from Sumatra.
• In 1892, Pierre Marie Heude named Rhinoceros annamiticus for a specimen from Vietnam.

As of 2005, three Javan rhinoceros subspecies are recognized:
– R. s. sondaicus, the main subspecies, also called the Indonesian Javan rhinoceros.
– R. s. inermis, known as the Indian Javan rhinoceros or lesser Indian rhinoceros.
– R. s. annamiticus, called the Vietnamese Javan rhinoceros or Vietnamese rhinoceros.

Early ancestors of rhinoceroses split from other odd-toed mammals during the Early Eocene. Studies of DNA from mitochondria suggest that modern rhinoceros ancestors separated from horse ancestors about 50 million years ago. The Rhinocerotidae family, which includes living rhinoceroses, first appeared in the Late Eocene in Eurasia. Rhinoceros ancestors began spreading from Asia during the Miocene.

The last common ancestor of living rhinoceroses in the subfamily Rhinocerotinae is believed to have lived about 16 million years ago. The ancestors of the genus Rhinoceros diverged from other living rhinoceroses around 15 million years ago. The genus Rhinoceros is more closely related to the Sumatran rhinoceros, as well as to the extinct woolly rhinoceros and the extinct Eurasian genus Stephanorhinus, than to African rhinoceroses. However, some genetic exchange occurred between ancestors of African rhinoceroses and Rhinoceros, as well as between Rhinoceros ancestors and woolly rhinoceros or Stephanorhinus ancestors.

A cladogram showing relationships of recent and Late Pleistocene rhinoceros species (excluding Stephanorhinus hemitoechus) based on whole nuclear genomes includes:
– Elasmotherium sibiricum
– White rhinoceros (Ceratotherium simum)
– Black rhinoceros (Diceros bicornis)
– Woolly rhinoceros (Coelodonta antiquitatis)
– Merck's rhinoceros (Stephanorhinus kirchbergensis)
– Sumatran rhinoceros (Dicerorhinus sumatrensis)
– Javan rhinoceros (Rhinoceros sondaicus)
– Indian rhinoceros (Rhinoceros unicornis)

The oldest confirmed fossils of the Javan rhinoceros are from the Late Pliocene in Myanmar, Java, and Pakistan. Studies suggest the Indian and Javan rhinoceroses split about 4.3 million years ago. A fossil astragalus (a bone in the ankle) from the Late Miocene in Myanmar, similar to that of the Javan rhinoceros, has been identified as Rhinoceros cf. R. sondaicus.

Description

Javan rhinos are smaller than Indian rhinoceroses and are about the same size as black rhinoceroses. They are the largest animal on the island of Java and the second-largest animal in Indonesia after the Asian elephant. A Javan rhino, including its head, is 2 to 4 meters (6.6 to 13.1 feet) long and can be 1.4 to 1.7 meters (4.6 to 5.6 feet) tall. Adult Javan rhinos weigh between 900 and 2,300 kilograms (2,000 to 5,100 pounds), though no study has measured them directly because they are so endangered. Males and females are similar in size, but females may be slightly larger. Rhinos in Vietnam appear smaller than those in Java, based on evidence from photos and footprints.

Like the Indian rhino, the Javan rhino has one horn, while other living rhino species have two horns. Its horn is the smallest among all living rhinos, usually less than 20 centimeters (7.9 inches) long, with the longest recorded horn being 27 centimeters (11 inches). Only males have horns, and females remain hornless as adults, though some may develop a small bump. Javan rhinos rarely use their horns to fight. Instead, they use them to scrape mud from wallows, pull down plants, and clear paths through thick vegetation. Like black and Sumatran rhinos, Javan rhinos have a long, pointed upper lip to help grab food. Their lower teeth are long and sharp, which they use during fights. Behind these teeth, two rows of six molars with flat tops are used to chew tough plants. Like all rhinos, Javan rhinos have good senses of smell and hearing but very poor eyesight. They are believed to live 30 to 45 years.

Javan rhinos have hairless skin that is gray or gray-brown and folds over their shoulders, back, and rump. This skin has a natural mosaic pattern that makes the rhino look armored. The folds on their necks are smaller than those of Indian rhinos but still form a saddle shape over the shoulders. Because they are so endangered, Javan rhinos are mainly studied through fecal samples and camera traps. They are rarely seen, measured, or observed directly.

Distribution and habitat

Fossil remains of Javan rhinoceroses have been found at the ancient Hemudu site in Zhejiang, China. An ancient Chinese text from the 4th century BCE, called the Classic of Mountains and Seas, seems to describe a Javan rhinoceros living near the Yangtze River. Fossil evidence from the Pleistocene era has also been found in the Tam Hay Marklot cave in northeastern Laos.

Historically, Javan rhinoceroses lived in many areas, including parts of Assam and Bengal in India, Myanmar, Thailand, Cambodia, Laos, Vietnam, the Malay Peninsula, and the islands of Sumatra, Java, and Borneo. Today, the species is only found in Ujung Kulon National Park in southwestern Java, where fewer than 100 individuals remain.

The Javan rhinoceros’s range has been shrinking for at least 3,000 years. Around 1000 BC, their northern range extended into China, but they began moving southward at about 0.5 km (0.31 mi) per year as human populations grew. They likely disappeared from India in the early 1900s. By 1932, they were extinct on the Malay Peninsula. The last Javan rhinoceroses on Sumatra are believed to have died during World War II. They may have also lived on Borneo, but these animals might have been Sumatran rhinoceroses, a different species that still survives there.

Javan rhinoceroses were seen in the Sunderbans between 1630 and 1908, but only six were thought to remain by 1892.

By the end of the Vietnam War, Javan rhinoceroses were believed to be extinct across mainland Asia. Some people in Cambodia claim to have seen them in the Cardamom Mountains, but no evidence has been found. In the late 1980s, a small group was discovered in Vietnam’s Cat Tien area, but the last individual there was killed in 2010. The population in Cat Tien National Park was declared locally extinct in 2011.

Javan rhinoceroses live in dense, lowland rainforests, grasslands, and wet areas with rivers, floodplains, or mud wallows. While they once preferred low-lying regions, the subspecies in Vietnam was forced to live at higher elevations (up to 2,000 m or 6,561 ft) due to human activity and hunting.

Behavior

The Javan rhinoceros usually lives alone, except when it is mating or when a mother is with her calf. Occasionally, they gather in small groups near salt licks and mud wallows. Rolling in mud is a common activity for all rhinos. This helps them stay cool and protects them from disease and parasites. The Javan rhinoceros does not dig its own mud wallows. Instead, it uses existing wallows made by other animals or natural pits, enlarging them with its horn. Salt licks are important because they provide essential nutrients from the salt. Male rhinos have larger home ranges, covering 12–20 km (4.6–7.7 sq mi), compared to females, which range from 3–14 km (1.2–5.4 sq mi). Male territories overlap less than female territories. It is unknown whether territorial fights occur.

Male rhinos mark their territory by creating dung piles and spraying urine. They also use foot scrapes in the ground and bent saplings to communicate. Other rhino species sometimes defecate in large dung piles and then scratch their feet in the dung, but Javan and Sumatran rhinos do not do this. Scientists believe this behavior may not be useful in the wet forests of Java and Sumatra for spreading scents. Javan rhinos are less vocal than Sumatran rhinos, and very few of their sounds have been recorded. Adult Javan rhinos have no natural predators except humans. In Vietnam, they are very cautious and hide in dense forests when humans are nearby. While this helps them survive, it makes them hard to study. If humans get too close, Javan rhinos may become aggressive, using their lower jaw teeth to stab and their heads to push upward. Their less social behavior may be a recent change due to population pressures. Historical evidence suggests they were once more social, like other rhino species.

The Javan rhinoceros eats only plants, including young leaves, branches, and fallen fruit. Many of these plants grow in sunny areas like forest clearings and shrublands. The rhino knocks down small trees to reach its food and uses its flexible upper lip to grasp it. It is the most adaptable eater among rhino species. Today, it eats only plants, but it likely ate both plants and grasses in the past. The rhino consumes about 50 kg (110 lb) of food each day. Like the Sumatran rhino, it needs salt in its diet. Salt licks, which were common in its historical range, are not found in Ujung Kulon. However, rhinos there have been seen drinking seawater, probably to meet their salt needs.

Conservation

The main reason for the ongoing decrease in the Javan rhinoceros population is poaching for their horns, a problem that affects all rhino species. Horns have been traded in China for more than 2,000 years because people believe they have healing powers. In the past, rhino hides were used to make armor for soldiers in China, and some groups in Vietnam thought the hides could help treat snake bites. Since rhinos live in areas where many people are poor, it has been hard to stop people from killing them for the money their horns can bring. In 1975, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) listed the Javan rhinoceros under Appendix I, which means trading rhinos or their products internationally is not allowed. Studies of the black market show that rhino horns from Asia can cost up to $30,000 per kilogram, three times the price of African rhino horns.

Loss of habitat due to farming has also caused the Javan rhinoceros population to decline, though this is less of a problem now because rhinos only live in one protected national park. Poor habitat conditions have made it harder for rhino populations that were hurt by poaching to recover. Even with conservation efforts, the future of the species remains uncertain. Because the rhinos live in a small area, they are at risk of disease and health problems caused by inbreeding. Scientists say a population of at least 100 rhinos is needed to keep the species' genetic diversity alive.

The Ujung Kulon peninsula in Java was destroyed by the 1883 eruption of Krakatoa. After the eruption, Javan rhinos returned to the area, and because humans did not return in large numbers, the peninsula became a safe place for wildlife. In 1931, when Javan rhinos were nearly extinct in Sumatra, the Dutch East Indies government made the rhino a legally protected species, a status it still holds today. A count of rhinos in Ujung Kulon in 1967 found only 25 animals. By 1980, the population had doubled and stayed around 50. Although rhinos in Ujung Kulon have no natural predators, they compete with wild cattle for limited resources, which may keep their numbers low. The Indonesian Ministry of Forestry manages Ujung Kulon. In 2006, evidence of at least four baby rhinos was found, the most recorded for the species.

In March 2011, a video from hidden cameras showed adults and young rhinos, suggesting recent breeding. Between January and October 2011, cameras captured images of 35 rhinos. By December 2011, a rhino-breeding sanctuary covering 38,000 hectares was being planned to help increase the population to 70–80 rhinos by 2015.

In April 2012, the World Wildlife Fund (WWF) and the International Rhino Foundation added 120 cameras to the existing 40 to monitor rhino movements and population size. A recent survey found fewer female rhinos than males in the eastern part of Ujung Kulon, which could slow efforts to save the species.

In 2012, the Asian Rhino Project worked to remove arenga palm, a plant that was spreading in the park and reducing rhino food sources. By following rhino trails, scientists studied their eating habits in the wild. Comparing the acid-insoluble ash content in rhino feces and their food helped estimate how well they digest food, a method that could be used in other areas where collecting all feces is not possible. Scientists found that rhinos with larger home ranges ate more varied food and used more wallow holes. Food quality and quantity varied among rhinos and over time. Larger rhinos used more energy, and the digestibility of plants depended on the rhino’s age and habitat conditions.

In May 2017, Bambang Dahono Adji, Director of Biodiversity Conservation at the Indonesian Ministry of Environment and Forestry, announced plans to move rhinos to the Cikepuh Wildlife Sanctuary in West Java. Before relocation, DNA tests would be done to avoid problems like inbreeding. As of December 2018, these plans had not been carried out.

In December 2018, the Javan rhino population was severely threatened by a tsunami caused by the nearby volcano Anak Krakatau.

In 2024, officials reported that arrested poachers admitted to killing 26 Javan rhinos, possibly reducing the population by one-third. At least four Javan rhino calves were recorded between August 2023 and 2024, including one seen in May 2024 that was estimated to be 3–5 months old.

Once common in Southeast Asia, the Javan rhino was thought to be extinct in Vietnam by the mid-1970s, at the end of the Vietnam War. The war damaged ecosystems through the use of napalm, Agent Orange, aerial bombing, landmines, and overhunting by poachers.

In 1988, a hunter shot an adult female rhino in Vietnam, proving the species had survived the war. In 1989, scientists found fresh rhino tracks along the Dong Nai River, suggesting up to 15 rhinos lived in the area. Because of the rhinos, the region became Cat Tien National Park in 1992.

By the early 2000s, it was feared the Vietnam population had declined beyond recovery, with estimates of only 3–8 rhinos remaining, possibly no males. Conservationists debated whether to introduce rhinos from Indonesia to save the population or if it could recover on its own.

In 2009–2010, genetic tests of dung samples in Cat Tien National Park showed only one Javan rhino remained. In May 2010, a Javan rhino’s body was found in the park, shot and its horn removed by poachers. In 2011, the International Rhino Foundation confirmed the Javan rhino was extinct in Vietnam, leaving only the rhinos in Ujung Kulon.

Javan rhinos have not been displayed in zoos for over 100 years. In the 19th century, at least four rhinos were shown in Adelaide, Calcutta, and London. At least 22 Javan rhinos were kept in captivity, though the actual number may be higher because they were sometimes mistaken for Indian rhinos.

Javan rhinos did not survive well in captivity. The oldest lived to be 20, about half the age they reach in the wild. No captive Javan rhino is known to have given birth. The last captive Javan rhino died in 1907 at the Adelaide Zoo in Australia, where the species was mistakenly labeled as an Indian rhino.

In 2025, a male rhino named Mustofa was successfully moved from the wild to the Javan Rhino Study and Conservation Area in Ujung Kulon National Park, becoming the first captive Javan rhino in

In culture

The Javan rhinoceros lived in Cambodia in the past. At least three images of rhinos are carved into the temple at Angkor Wat. In the west wing of the North Gallery, a carving shows a rhino with a god believed to be Agni, the fire god, riding on its back. Scientists think these rhinos are Javan rhinoceroses, not the similar-looking Indian rhino, because of a skin fold on the shoulder that runs along the back, creating a saddle-like shape. Another carving in the east wing of the South Gallery shows a rhino attacking people in a scene of heaven and hell. The temple’s architect was likely an Indian Brahmin priest named Divakarapandita, who lived from 1040 to 1120 AD and worked for several kings, including Suryavarman II, who built the temple. The Indian priest may have influenced the carvings of bumps on the rhinos’ skin, which resemble those of Indian rhinos, while local Khmer artists added other details based on the more familiar Javan rhino. In Khmer culture, the rhinoceros is uniquely linked to Agni as his vehicle, or vahana. Another rhino carving, placed in a circle with elephants and water buffalo, is found at the Ta Prohm temple. Some people suggest this carving might represent a stegosaur because of leaf-like shapes behind it that look like plates. The mascot for the 2023 FIFA U-20 World Cup is a Javan rhinoceros named Bacuya.