Javan Rhinoceros

Limited to just a single national park, the Javan rhino today numbers just 72 individuals in the wild

The Javan rhinoceros (also known as the lesser one-horned rhinoceros and the Sunda rhinoceros) is a species of rhinoceros native to of Southeast Asia. The Javan rhinoceros is thought to be most closely related to the Indian rhinoceros, both of which only have one horn.

As of 2019, it’s estimated just 72 Javan rhinos survive in a single national park named Ujung Kulon on the Indonesian island of Java’s westernmost tip. However, with no poaching of the species reported in more than 25 years at Ujung Kulon, there’s hope for the species’ survival.

Incredible Javan Rhinoceros Facts!

• The Javan rhinoceros once roamed from India, to Vietnam, and south to the islands of Indonesia. The last mainland Javan rhino was poached in 2010, leaving the subspecies of mainland Javan rhinos extinct.
• Female Javan rhinos often lack a horn or have a small “nub.”
• Today, the Javan rhino is found in only a single national park that sits 37 miles (60 km) from an active volcano that’s erupted as recently as December, 2019.

Scientific Name and Evolution

The scientific name for the Javan rhinoceros is Rhinoceros sondaicus. Along with the Indian rhinoceros, the Javan rhino is in the genus Rhinoceros, which is Greek for ‘nose’ and ‘horn’ and comprises the two species of one-horned rhinos. Sondaicus refers to ‘Sunda,’ a name for the Southeastern Asia where Javan Rhinos historically lived.

Javan Rhinos are more closely related to Indian Rhinos, of course, and may have diverged from them in evolution around 11 million years ago. While they have their differences from the other species of rhinos, they all adapted their thick, protective hide in order to protect themselves from would-be attackers. Add to that their imposing horns, there are not many animals on earth that could survive a rhino rush and gore attack!

Appearance

The Javan rhino is smaller than the Indian rhinoceros, weighing 900 to 2,300 kg (2,000 to 5,100 lbs). Its length stretches 3.1 to 3.2 m (10 to 10.5 ft).

The Javan rhino closely resembles Indian rhinos. Both species have a single horn, though female Javan rhinos often lack a horn or have a small “nub” on their nose. In addition, the Javan rhino’s skin folds aren’t as pronounced as the Indian rhino’s. This gives the species less of a look of having “body armor.”

Due to the extreme rarity of Javan rhinos, they’ve been studied as the least of all rhino species. Today, few pictures are taken of Javan rhinos, with most studies coming from camera traps in the dense forests it inhabits in Ujung Kulon National Park.

Habitat

The Javan Rhino primarily inhabits dense lowland rain forests, tall grass, and reed beds that are plentiful with rivers, large floodplains, or wet areas with many mud wallows. The range of Javan rhinoceros once stretched from Bengal, through Southeast Asia, and down to Sumatra but today, the Javan rhinoceros is only found on the island of Java.

Where the Javan rhinoceros is found today: Ujung Kulon

Today, the Javan rhino is known to survive in just a single habitat, the Ujung Kulon National Park on the western edge of the island of Java. The national park measures only about 498 square kilometers (192 sq. mi), which means all Javan rhinos live in an area about the same size as the city of Tulsa, Oklahoma.

While Javan rhinos were either hunted to extinction or lost their habitat across Southeast Asia, they survived in Ujung Kulon after unique circumstances. In 1883 a massive volcano named Krakatoa erupted off the coast of Indonesia and decimated surrounding areas. After the event, humans fled the area, but rhinos and many other critically endangered species began repopulating there.

Today, Ujung Kulon provides a protected environment that has allowed Javan rhino populations to stabilize, but it can only support a limited amount of rhinos within its borders.

Population

The population of Javan rhinos was estimated at 72 individuals by the International Rhino Foundation in 2019.

While this population makes the Javan rhino one of the most critically endangered mammals on Earth, it has been stable for more than 30 years and their population has increased from an estimated 50 individuals across the past decade. Learn more about the most endangered species in the world here.

Extinct Javan rhino subspecies

Historically there were three subspecies of Javan rhinoceros. In addition to the subspecies that survive today, there were the Indian Javan rhinoceros and the Vietnamese Javan rhinoceros.

Today, both the Indian Javan rhinoceros and the Vietnamese Javan rhinoceros have been declared extinct. A small species of Javan rhinos were found in Vietnam’s Cat Tien park, but the last surviving member of the subspecies was found poached in 2010.

Diet

The Javan rhino is a herbivore that browses across shrubs, bushes, and saplings. Javan rhinos browse the densely vegetated sub-tropical forest for leaves, flowers, buds, fruits, berries, and roots which they dig up from the ground using their horns.

Due to Javan rhinos being restricted to a small habitat, it’s hard to know how varied their diet was across their historical range. With Javan rhino populations have ranged all the way to the dense grasslands of India, it’s likely the species once grazed as well.

Predators

The Javan rhino faces few predators in the wild. Javan tigers existed in Ujung Kulon until the 1960s, but have been declared extinct. A small population of Javan leopards survive in Ujung Kulon and could prey on rhino calves and weaker individuals.

With no human poaching reported in the rhino’s surviving habitat in the past 25 years, its greatest threat today is a lack of genetic diversity that threatens breeding numbers.

Reproduction and Life Cycles

With an extremely small population and long gestation periods, the birth of any Javan rhino is closely monitored. In December 2019, four new calves were spotted, increasing the population to an estimated 72 rhinos.

Like all rhino species, the Javan rhino has a long gestation period, making repopulating challenging. Since no Javan rhinos are held in captivity, their gestation period isn’t precisely known. However, it’s believed to be roughly 15 to 16 months.

Facts

• Living in the shadow of a volcano – The remaining Javan rhino population survived after repopulating an area devasted by the eruption of the volcano Krakatau in 1883. However, the species today faces the threat of natural disasters as a nearby volcano named Anak Krakatau continues erupting.
• A close scare in 2018 – Anak Krakatau lays just 37 miles (60 km) from the coast of the Javan rhino’s single remaining habitat. In December 2018, the volcano erupted and unleashed a tsunami that killed two park rangers at Ujung Kulon. It’s believed no Javan rhinos were harmed, but the event demonstrates the risks that remain with all rhinos living in a habitat that’s susceptible to natural disasters.
• 145 million people and 72 Javan rhinos – One of the challenges to repopulating the Javan rhino is the loss of suitable habitats across Java. The island is only about the size of Arkansas (population: 3 million), but is home to about 145 million people. This growth in population has left few suitable habitats for large Javan rhino populations.