Javan rhinos are one of the most endangered animals on the planet and the rarest of the world’s five remaining rhino species. While they once roamed across South and Southeast Asia, all remaining Javan rhinos now live in Ujung Kulon National Park, a protected area on the island of Java, Indonesia.
Also called the lesser one-horned rhinoceros, the Javan rhino is smaller than the Indian rhino (Rhinocerosunicornis), also known as the greater one-horned rhinoceros. While these two Asian rhino species share many similarities, Javan rhinos have smaller heads and less apparent skinfolds than Indian rhinos.
Both male and female Javan rhinos have lower tusk-like incisors, which they sometimes use for fighting, though only males have a small black horn at the tip of their snout. This means that female Javan rhinos are the only extant rhinos that remain hornless into adulthood.
With limited opportunities to measure and weigh Javan rhinoceroses, experts estimate that the species can be up to 3.2 metres (11 feet) long and weigh up to 2,300 kilograms (5,070 pounds). At birth, baby Javan rhinos weigh between 40 and 64 kilograms and are around the size of a large dog. A female Javan rhino births a calf every four to five years after a long 16-month gestation period.
Despite their bulk, Javan rhinos are active climbers and excellent swimmers. These skills help them navigate the marshes, tropical forests, and areas of thick bush they inhabit. When foraging for food, male Javan rhinos use their horns to pull down plants or open up pathways through thick vegetation. As megaherbivores, Javan rhinos eat huge quantities of shoots, twigs, fruit, tall grasses, shrubs, and leaves. Biologists have identified that Javan rhinos eat more than 100 different plant species, making them the most adaptable feeders of all rhinos.
The Javan rhino’s diet and eating behaviours are two reasons why they play such a vital role in their ecosystem. By consuming an estimated 50 kilograms (110 pounds) of plant material in a day and trampling vegetation as they forage, Javan rhinoceroses make room for new plants to grow and help the forest stay healthy so it can store more carbon dioxide and produce more oxygen. Javan rhinos also disperse the seeds of the plants and fruit they eat through their faeces, encouraging the growth of new plant life and improving the spread of biodiversity within the forest and beyond.
What is a Javan rhino’s scientific name?
The scientific name for the Javan rhino is Rhinoceros sondaicus. The genus Rhinoceros is a combination of the ancient Greek words ris—meaning nose—and keras—meaning horn of an animal. The species name sondaicus refers to Sunda, the biogeographical region that includes the islands of Borneo, Java, Sumatra, and surrounding smaller islands.
Are Javan rhinos endangered?
The International Union of the Conservation of Nature (IUCN) last assessed the status of Javan rhinos in 2019 and classified them as critically endangered. They face a range of threats, including illegal trade, loss of habitat and food availability, and disease.
Where do Javan rhinos live?
Javan rhinos inhabit forests, marshlands, and areas covered in thick bush and bamboo. The species used to have a wide geographical spread, living in many countries and locations throughout South and Southeast Asia. These included the islands of Java, Borneo, and Sumatra, the Malay peninsula, Vietnam, and an area that extended through Myanmar into the state of Assam, India as well as Bangladesh.
The last known population of Javan rhinos in mainland Asia were living in Cat Loc, Vietnam, until the final remaining rhino was poached in 2010. This conservation tragedy then made Ujung Kulon National Park in Java, Indonesia the only remaining place on Earth with a population of Javan rhinos.
Javan rhinos have become—and remain—a critically endangered species due to illegal trade, reduced habitat, limited food availability, and disease.
One of the main reasons why Javan rhinos are critically endangered is due to poaching and the illegal trade of their parts. In particular, the excessive demand for rhino horn in traditional Chinese medicine has been detrimental to the survival of this species. Rhino horns are ground down and processed into pills, tonics, and powders.
In China and Vietnam, rhino horns are seen as luxury health tonics and status symbols among some groups of buyers. This trend is especially worrying for conservationists as neither rising prices nor the dwindling worldwide rhino population appear to have any effect on this demand for rhino horns.
Unlike their desert-dwelling African cousins, Javan rhinos thrive in humid, tropical areas. However, as their rainforest habitats disappear due to deforestation and human expansion, it becomes more difficult for Javan rhinos to feed and survive.
Given that the entire current population of Javan rhinos lives in Ujung Kulon National Park, the carrying capacity of their current habitat may also limit the possibility of population growth.
Food availability and natural competition
The predominance of the palm species Arenga obtusifolia in Ujung Kulon is another threat to the Javan rhino habitat. Known locally as langkap, this invasive plant crowds out sunlight and prevents the plants Javan rhinos eat from growing.
Arenga currently covers an estimated 18,000 hectares (44,479 acres) or 60% of the peninsular section of the national park. To combat the spread of the palm, workers in the Javan Rhino Study and Conservation Area began a removal and management effort in 2010. They have since cleared 150 hectares (371 acres) of the plant.
Ujung Kulon is also home to up to 800 Javan banteng (Bos javanicus). Although banteng are primarily grazers, their feeding ecology overlaps with Javan rhinos when grass is in short supply. With suitable rhino foods already scarce, this natural competition limits the availability of foraging plants for rhinos. This, in turn, contributes to a slow decline in Javan rhino numbers within the park.
Conservation attempts to establish a new group of Javan rhinos within Ujung Kulon have been thwarted because of a disease called hemorrhagic septicemia (HS) in the park’s water buffalo population. Periodic Javan rhino deaths seemingly as a result of HS have been occurring, with the loss of at least five individuals found dead with their horns intact between 2016 and 2022. With no evidence of poaching, disease transmission from buffalos is the most likely cause of death.
Learn more about Javan rhinos with these quick facts.
What is a Javan rhino?
Javan rhinos are one of three Asian rhinos still in existence and the rarest of all five remaining rhino species in the world—a tragic statistic that belies their powerful, armoured appearance.
Javan rhinos are slightly larger than Sumatran rhinos (Dicerorhinus sumatrensis) but smaller than Indian rhinos, black rhinos (Diceros bicornis), and white rhinos (Ceratotherium simum). Regardless, Javan rhinos are far from small creatures—they can reach lengths of up to 3.2 metres (nearly 11 feet) and weigh up to 2,300 kilograms (5,070 pounds).
Female Javan rhinos are unique as the only extant rhino that remains hornless into adulthood. While male Javan rhinos have a black horn at the tip of their snout, it is the smallest horn of the Rhinocerotidae family, measuring less than 20 centimetres (7.9 inches).
What is the Javan rhino's habitat?
Javan rhinos thrive in forests, marshlands, and regions covered in thick bush and bamboo. This species prefers moist, tropical and subtropical environments—especially those with access to water holes and mud puddles. They often take dips or wallow in mud to keep their body temperature down and prevent disease.
Where are Javan rhinos found?
In the past, Javan rhinos occupied the islands of Java, Borneo, and Sumatra, the Malay Peninsula, Vietnam, and an area extending through Myanmar into India and Bangladesh. Now, the entire species is restricted to Ujung Kulon National Park—a protected area on the island of Java in Indonesia.
What do Javan rhinos eat?
Javan rhinos eat an estimated 50 kilograms of food each day and follow a diet of leaves, shoots, tall grasses, twigs, and fallen fruit. Biologists have identified over 100 different plant species consumed by Javan rhinos, making them the most adaptable feeders of all rhino species.
How do Javan rhinos reproduce?
Why are Javan rhinos important?
Javan rhinos are a keystone species—one whose presence in their ecosystem has a disproportionately positive effect on other organisms within it. Through behaviours like wallowing in mud, consuming large quantities of plantlife, and dispersing seeds through their faeces, Javan rhinos help regulate and improve the ecosystems they inhabit by shaping the land, spreading nutrients, hosting large numbers of ectoparasites, and modifying vegetation. All this, in turn, encourages biodiversity in the growth of new plants, and provides food and easier access to water for many birds, insects, and animal species.
Is the Javan rhino extinct?
The Javan rhino isn’t extinct, but there are very few left in the wild.
How many Javan rhinos are left?
The exact Javan rhino population is unknown, but estimates from 2021 indicate that there are about 76 remaining individuals in the wild.
Why are Javan rhinos endangered?
Javan rhinos became endangered primarily because of poaching, although habitat loss and disease are also key factors in their continuing decline.
The low reproduction rate of Javan rhinos makes the process of increasing their small population slow and difficult, so it’s likely that the species will remain critically endangered for some years to come. Plus, with no new habit to move into beyond Ujung Kulon National Park, the current population is at great risk of disease and natural disasters.
How are Javan rhinos being protected?
Although no Javan rhinos have been poached for over a decade, it remains a top priority to protect them and their habitat. Park authorities in Ujung Kulon have stepped up their monitoring systems and now have camera traps covering the entire park. Additionally, the removal of the invasive Arenga palm from the area helps promote better food availability for Javan rhinos.
As demand for rhino horns remains high in parts of China and Vietnam in particular, the tireless work of conservation groups like IFAW protects Javan rhinos by cracking down on wildlife crime, investigating what drives it, and teaching the public how to avoid the products it creates.
How can we help Javan rhinos?
First and foremost, refuse to buy rhino horns and derived products. While it’s too late to help the rhinos used in those items, refusing to support this practice helps Javan rhinos by making their horns less desirable for buyers and less profitable for poachers.
Supporting organisations such as IFAW also helps Javan rhinos by funding vital initiatives to ensure their ongoing safety and secure their future survival.
IFAW is involved in various projects supporting the protection and conservation of endangered species like Javan rhinos. One such project was an undercover investigation by IFAW and its partners, the Jakarta Animal Aid Network (JAAN) and the Wildlife Trust of India (WTI), which exposed online illegal wildlife trafficker networks in Indonesia.
IFAW is also working with various partners to strengthen animal protection and enforcement, reduce the demand for products procured via poaching, and disrupt wildlife cybercrime as part of its comprehensive Wildlife Crime Program. As Wildlife Cybercrime Prevention becomes more of a priority, IFAW is working with nearly 50 different technology companies to end wildlife trafficking online.
How can you help?
As one of the largest animal welfare and conservation charities in the world, IFAW is doing everything in its power to safeguard populations and preserve the habitats of endangered animals such as Javan rhinos.