Indonesian Javan rhinoceros

The Indonesian Javan rhino is the only viable population of Javan rhino left on the planet.
 / ©: / Andy Rouse / WWF
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© / Andy Rouse / WWF
Javan rhinoceros photographed by a camera trap, Ujung Kulon National Park, Java, Indonesia.
© Mike Griffiths / WWF

Population stable, but still too small

  • Common Names

    Indonesian Javan rhinoceros, lesser one-horned rhino; Rhinocéros de la Sonde (Fr); Rinoceronte de Java (Sp)

  • Scientific Name

    Rhinoceros sondaicus sondaicus

  • Location

    Java, Western Indonesia

  • Status

    Critically Endangered


  • Population

    28-56 in Ujung Kulon National Park

Population & distribution

Previous population & distribution
Javan rhinos were once found on all major volcanoes in west Java, some of which are 3,000m above sea level. During the 1960s an estimated 20-30 individuals remained in Ujung Kulon National Park.

The population doubled from 1967 to 1978, after rigorous protection was put in place, in part supported by WWF-Indonesia. Since the end of 1970s, population numbers appear to be stable.

Current population & distribution
Only one population survives, in Ujung Kulon on the island of Java, Indonesia. The species has been protected here since 1931 in Indonesia and Ujung Kulon National Park was set aside for the conservation of the species.

The current population size is estimated at 28-56 individuals. 

Ujung Kulon has an estimated carrying capacity of 80 rhinos, based on home size range and habitat condition. However, rhino numbers have not increased significantly for some years, indicating that carrying capacity might have already been reached.

Other possible reasons for the stable numbers are: (1) habitat changes, which have led to a decrease in available food; (2) competition with banteng (a cattle species) for food; (3) skewed sex ratio, leading to difficulties in mating; and (4) inbreeding depression.


Major habitat type
Tropical and Subtropical Moist Broadleaf Forests

Biogeographic realm

Range States

Geographical Location
Western Indonesia

Ecological Region
Western Java Mountain Forests


Not much is known about the breeding biology of the Indonesian Javan rhino, as it has never bred in captivity.

Mating takes place each year but is only successful every 4-5 years. The mating season occurs roughly from July to November, and the gestation period is about 16 months.

The single offspring is active soon after birth, being suckled by the mother for at least one and perhaps two years.

In Ujung Kulon, females become sexually mature between the age of 6 and 8, and research suggests that they mark their territory with urine in order to breed. The young stays with its mother for 1-2 years.

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