Javan Rhino Q & A

 

Q: How tall are Javan rhinos?

A: Javan rhinos are, on average, between 5 and 5 ½ feet tall (1.5 - 1.7 meters).

 

Q: How heavy are Javan rhinos?

A: Javan Rhinos can weigh anywhere between 2,000 and 5,060 pounds (900 - 2,300 kilograms). Females are smaller than males.

 

Q: What is the average horn weight of a Javan rhino?

A: The horn of a male Javan Rhino can reach approximately 26 cm (10 inches) in length; females typically have no horn or just a knob. Our field staff estimates that the average horn weight is 1 to 3 pounds, based on several recent horn samples collected from rhino carcasses.

 

Q: How long do Javan rhinos live?

A: We don’t know exactly how long Javan rhinos live, but their life span is estimated at 30 – 40 years.

 

Q: When do Javan rhinos reach sexual maturity?

A: Sexual maturity varies depending on the sex of the rhino. Females probably reach sexual maturity at 5 – 7 years of age, and males probably reach sexual maturity around 10 years of age.

 

Q: What is the gestation period for Javan rhinos? 

A: Female Javan rhinos give birth to one calf at a time, most likely every two to three years. We believe that the gestation period is similar to other rhino species, which means that Javan rhino moms are probably pregnant for 15 or 16 months before giving birth.

 

Q: Are they browsers or grazers?

A: Javan rhinos seem to be more willing to eat different types of plants than other rhino species. In the tropical rain forest where the species now survives, it is a pure browser, and plucks leaves and branches from a variety of trees to eat. But it is possible that the Javan rhino was a mixed feeder (eating both browse and grass) in other parts of its historic range where the species is generally believed to have occupied more lowland areas, especially along rivers.

Q: Do both sexes scent-mark with their scat? 

A: Male Javan rhinos mark their territories with urine, feces, tree scrapes, and twisted saplings. A rhino passing through a new area will then use its excellent sense of smell to detect these markings and will know that the territory “belongs” to another rhino. It is much less common for females to scent-mark, although it is possible.

Q: Without human pressures, what would their ideal habitat be? 

A: Currently, Javan rhinos live in lowland tropical rainforest. Historically, the species was much more widespread and inhabited lowland rainforest, wet grasslands and large floodplains.

 

Q: Are Javan rhinos social animals? Do they interact with other species?

A: The Javan rhino is largely solitary, although calves stay with their mothers after birth, for up to two years. Sometimes Javan rhinos gather in a group at a mud wallow or salt lick (a small hot spring where water full of minerals seeps or bubbles out of the ground). Based on research carried out in Ujung Kulon National Park, it is thought that males have larger ranges than females (up to 30 square miles) and are much more territorial, although there is little evidence they actively defend their territory by fighting. Generally, the Javan rhino does not interact with other species and they certainly try to avoid humans.

Q: Are there, or were there, any sub-species?

A: Most scientists believe there were currently two sub-species of Javan rhino, the “Indonesian” Javan rhinos in Ujung Kulon National Park and now-believed-to-be-extinct  “Vietnamese” Javan rhinos formerly living in Cat Tien National Park.

 

Q: Approximately how many Javan rhinos are left in the wild, and with the recent increase of rhino poaching in Africa, are the Javan rhinos still the most endangered?

A: The Javan rhino is classified as Critically Endangered under the IUCN Red List, meaning that the species is facing an extremely high risk of extinction in the wild. There are just two known populations of Javan rhino remaining. Ujung Kulon National Park on the island of Java in Indonesia holds between 38-44 rhinos, based on a 2008 census. The existence of a second population in Vietnam is less certain.  It is believed that the last Javan rhino was poached from Cat Tien National Park in southern Vietnam in 2010. The Javan rhino has the smallest population of any of the five rhino species. However, some scientists consider the Sumatran rhino (population approximately 200 individuals, also listed as Critically Endangered) to be the “most endangered” rhino species, because although there are more Sumatran rhinos than Javan rhinos, it population is declining at a far higher rate than Javan rhinos. What we do know for sure is that both of these species are facing extinction and we must act quickly to protect them.

Q: Why hasn’t there been a captive breeding program for Javan rhinos?

A: There are not currently any Javan rhinos in captivity, and so rhinos would have to be captured in the wild and moved into a captive facility to launch a captive breeding program. Like all endangered species around the world, the Javan rhinos in Ujung Kulon are ultimately managed by the Indonesian government, and the government would have to give official permission for a captive breeding program, which it has not yet done. There are also a number of other stakeholders (NGOs, community groups, etc.) involved in Javan rhino conservation who do not feel that captive breeding is the best option for saving this species. The scientific community knows very little about Javan rhinos in general, and even less about their breeding habits, so trying to create a captive breeding program would be a lengthy and daunting process. The option isn’t off the table, but at this time, the government of Indonesia and other stakeholders have agreed that the best option for increasing the population of Javan rhinos is to focus on increasing the amount of suitable habitat in Ujung Kulon National Park so that the wild population can increase on its own.

 

Q: Has anyone considered capturing the last remaining Javan rhinos in Vietnam and attempting to breed them with the Javan rhinos in Indonesia?

A: The IUCN Asian Rhino Specialist Group recommended that the “Vietnamese” Javan rhinos should be bred with the “Indonesian” Javan rhinos to try to increase the species’ population and to preserve genetic diversity.  Unfortunately, politics got in the way of saving the Vietnamese populaiton. The government of Vietnam would have to had given permission for the rhinos to be captured and translocated to another country, or the Indonesian government permission to transfer rhinos to Vietnam.  Neither government was willing to do this.