The Javan rhino is dusky grey. It can reach up 4m in length and 1.7m in height, and weigh as much as 2.3 tonnes. It is very similar in appearance to the closely related greater one-horned rhino
, although it is slightly smaller, has a much smaller head, and looser, less apparent skin folds.
The species has a single horn of about about 25 cm. The upper lip is pointed and can be used to grasp food and bring it to the mouth.
There are still major gaps in our knowledge about Javan rhinos because they are extremely difficult to study. The remaining Javan rhinos live in incredibly dense jungle and the species has never bred in captivity.
For these reasons, the average lifespan is unknown, but it is probably between 30-40 years. It is also assumed - based on the biology of the greater one-horned rhino - that females become sexually mature at 5-6 years and males at 10 years.
The mating season occurs roughly from July to November, but the gestation period is also unknown, athough it is probably around 16 months - similar to the greater one-horned rhino.
The Javan rhino is solitary, except when pairs form for mating and when mothers tend their young.
In the tropical rainforest where the species now survives, it is a pure browser, but it was possibly a mixed feeder (both browse and grass) in other parts of its historic range.
Population and distribution
The Javan rhino historically roamed across a vast swathe of Asia from north-eastern India through Myanmar, Thailand, Cambodia, Laos, Vietnam, and the Indonesian islands of Sumatra and Java.
But over the past 150 years, its range and population has shrunk dramatically. And now there is just one population in a single national park in the Ujung Kulon peninsula on the Indonesian island of Java. According to WWF’s latest figures, from 2019, the estimated population size is 66 (with a range of 66-69 individual animals).
The authorities are now considering creating a second population to ease the pressure on Ujung Kulon national park and give the species a greater chance of long term survival.
The last Javan rhino outside Ujung Kulon died in 2010 in Cat Tien National Park in Vietnam. It had been shot and its horn removed. The species was officially declared extinct in Vietnam the following year.