Bornean rhinoceros
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The Bornean rhinoceros (''Dicerorhinus sumatrensis harrissoni''), also known as the eastern Sumatran rhinoceros or eastern hairy rhinoceros, is one of three subspecies of
Sumatran rhinoceros The Sumatran rhinoceros (''Dicerorhinus sumatrensis''), also known as the Sumatran rhino, hairy rhinoceros or Asian two-horned rhinoceros, is a rare member of the family Rhinocerotidae and one of five extant species of rhinoceros. It is the o ...
. The subspecies may be
functionally extinct Functional extinction is the extinction of a species or other taxon such that: #It disappears from the fossil record, or historic reports of its existence cease; #The reduced population no longer plays a significant role in ecosystem function; or ...
, with only one individual, a female named Pahu, surviving in captivity, and held in the state of
Sabah Sabah () is a States and federal territories of Malaysia, state of Malaysia located in northern Borneo, in the region of East Malaysia. Sabah borders the Malaysian state of Sarawak to the southwest and the North Kalimantan province of Indone ...
. In April 2015, the Malaysian government declared the Bornean rhinoceros to be
extinct in the wild A species that is extinct in the wild (EW) is one that has been categorized by the International Union for Conservation of Nature as known only by living members kept in captivity or as a naturalized population outside its historic range due ...
in the Malaysian portion of
Borneo Borneo (; id, Kalimantan) is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java, west of Sulawesi, and eas ...
. However, in March 2016, a young female rhino was captured in
East Kalimantan East Kalimantan (Indonesian: ) is a province of Indonesia. Its territory comprises the eastern portion of Borneo. It had a population of about 3.03 million at the 2010 census (within the current boundary), 3.42 million at the 2015 census, and 3. ...
(in the Indonesian portion of Borneo), providing evidence of their continued existence.http://news.nationalgeographic.com/2016/03/160324-sumatran-rhino-borneo-indonesia-kalimantan-endangered-species/ The
International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
(IUCN) classifies the subspecies as critically endangered.


Taxonomy

The Bornean subspecies ''Dicerorhinus sumatrensis harrissoni'', was named in honour of the British polymath
Tom Harrisson Major (United Kingdom), Major Tom Harnett Harrisson, DSO OBE (26 September 1911 – 16 January 1976) was a British polymath. In the course of his life he was an ornithologist, explorer, journalist, broadcaster, soldier, guerrilla, ethnologist, mu ...
, who worked extensively with Bornean zoology and anthropology in the 1960s.


Physical descriptions

The Bornean rhinoceros is markedly smaller than the other two subspecies, making it the smallest of the extant rhinos. The weight of an adult individual ranges from 600–950 kg, the height from 1–1.5 meters and the bodylength from 2–3 m. The Bornean rhinoceros has the darkest skin of the Sumatran rhinos, and the fur of calves is much denser, but it becomes darker and more sparse as the animal matures. The head size is also relatively smaller. The rhinoceros has fringed ears and wrinkles around its eyes. Like the
Black rhinoceros The black rhinoceros, black rhino or hook-lipped rhinoceros (''Diceros bicornis'') is a species of rhinoceros, native to eastern and southern Africa including Angola, Botswana, Kenya, Malawi, Mozambique, Namibia, South Africa, Eswatini, Tanzania ...
it has a prehensile lip. The difference from the Western Sumatran rhinoceros is mainly genetic.


Habitat and distribution

Bornean rhinos used to range all over Borneo, but their range has been severely reduced. Previously, the entire known wild population lived in Sabah, mostly in the
Tabin Wildlife Reserve The Tabin Wildlife Reserve ( ms, Taman Hidupan Liar Tabin) is a nature preserve in Sabah, Malaysia. It was created in 1984 to preserve Sabah's disappearing wild animals. Occupying a large part of the peninsula forming the northern headland of D ...
. However, this population is now believed to be extinct. A recently captured specimen and video evidence from camera traps have confirmed their continued presence in East Kalimantan, now believed to hold the entire wild population. Reports of animals surviving in
Sarawak Sarawak (; ) is a States and federal territories of Malaysia, state of Malaysia. The largest among the 13 states, with an area almost equal to that of Peninsular Malaysia, Sarawak is located in northwest Borneo Island, and is bordered by the M ...
are unconfirmed. Today, the Bornean rhinoceros, like the Sumatran rhino, lives in hot, humid closed canopy
rainforest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...
. However, being a species which existed before the end of the
Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
, it is likely that this was not the habitat in which they evolved.


Behavior and ecology

The Bornean rhinoceros, like most rhinos, is a solitary animal that lives in dense rainforest and swamps. It usually feeds at dusk and bathes in mud during the day. The animals eat around 50 kg of plant matter per day. Rare minerals are gained from salt licks. These animals are very good swimmers and can maneuver well on steep slopes. They mark their territory with scrapings, bent saplings and scent marks. The Bornean subspecies may also be more of a browser than most Asian rhinos. In April 2007, it was announced that a
camera trap A camera trap is a camera that is automatically triggered by a change in some activity in its vicinity, like presence of an animal or a human being. It is typically equipped with a motion sensor – usually a passive infrared (PIR) sensor ...
in Sabah had captured footage of a Bornean rhinoceros eating and investigating the equipment. This was the first footage showing the elusive rhino's natural behavior in the wild.


Threats and conservation

By the start of the 1900s, the Bornean rhinoceros was common throughout its native range. But the population has declined dramatically, and has been reduced to an estimated 15 individuals. It is thought to be extinct in
East Malaysia East Malaysia (), or the Borneo States, also known as Malaysian Borneo, is the part of Malaysia on and near the island of Borneo, the world's third-largest island. Near the coast of Sabah is a small archipelago called Labuan. East Malaysia li ...
and most of
Kalimantan Kalimantan () is the Indonesian portion of the island of Borneo. It constitutes 73% of the island's area. The non-Indonesian parts of Borneo are Brunei and East Malaysia. In Indonesia, "Kalimantan" refers to the whole island of Borneo. In 2019, ...
and now can only be found in East Kalimantan. This animal is highly threatened by hunting,
poaching Poaching has been defined as the illegal hunting or capturing of wild animals, usually associated with land use rights. Poaching was once performed by impoverished peasants for subsistence purposes and to supplement meager diets. It was set a ...
for their horn,
habitat loss Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...
, and by having a small, scattered population. In the 1930s, a huge wave of hunting by natives wiped out much of the rhino's population. The natives killed the rhinos and traded their horns to
China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
. In traditional Chinese culture, rhino horns have special medicinal powers that can heal many ailments. Despite many scientific studies proving this to be false, the
market Market is a term used to describe concepts such as: *Market (economics), system in which parties engage in transactions according to supply and demand *Market economy *Marketplace, a physical marketplace or public market Geography *Märket, an ...
of rhino horns for Chinese medicine has continued, leading to poachers having further decimated the Bornean rhino's population. Using mining and logging roads which cut through already fragmented rainforest, poachers were able to more easily track down rhinos. Poachers continue to be one of the largest threats to the Bornean rhinoceros and local wildlife patrols were increased in November 2015 to protect the remaining population. Beginning in the 1960s, large-scale
logging Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidding, on-site processing, and loading of trees or logs onto trucks or skeleton cars. Logging is the beginning of a supply chain ...
for international consumption heavily degraded or completely cleared much of Borneo's rainforest. In 2013, it was found that 80% of
Malaysian Borneo East Malaysia (), or the Borneo States, also known as Malaysian Borneo, is the part of Malaysia on and near the island of Borneo, the world's third-largest island. Near the coast of Sabah is a small archipelago called Labuan. East Malaysia li ...
's forests were heavily impacted by logging. In the 1990s,
palm oil Palm oil is an edible vegetable oil derived from the mesocarp (reddish pulp) of the fruit of the oil palms. The oil is used in food manufacturing, in beauty products, and as biofuel. Palm oil accounted for about 33% of global oils produced from ...
became a huge industry in Borneo, having an even larger effect on rhinos and other native species. While animals can still survive in logged forests, palm oil plantations cannot support wildlife and thus completely wiping out the animals previously living in the area. The widespread habitat destruction and hunting of the Bornean rhinoceros soon led to the population being too fragmented to repopulate. Being extremely elusive and solitary animals, many individuals and populations were separated, making it nearly impossible for the animal's to find mates and reproduce. Many of the rhinos captured on camera traps and identified in the wild in the past decade have been largely isolated from other rhinos, and the remaining 15 animals are split up between three isolated populations. In 2008, it was estimated that there were around 50 rhinos left in the wild in Sabah, with this number dropping to only 10 in 2013. In April 2015, the Bornean rhinoceros was declared to be extinct in Sabah and thought to be completely extinct in the wild. In 2013, single rhino was identified in East Kalimantan through footprints and a single image caught by a camera trap. However, this individual was thought to be a lone specimen and the population was believed to have also gone extinct. Then, in March 2016, experts announced that 15 animals had been identified in the region, with researchers for the
World Wildlife Fund The World Wide Fund for Nature Inc. (WWF) is an international non-governmental organization founded in 1961 that works in the field of wilderness preservation and the reduction of human impact on the environment. It was formerly named the Wo ...
(WWF) capturing a live animal in a pit trap in Kutai Barat around the same time. The animal was identified as a female between the age of four and five years old. The discovery proved that the subspecies still existed in the wild and that there were potentially enough animals left to save them. Researchers hope to find at least 10 more animals. The WWF plans to create a new sanctuary for Bornean rhinos on 200 ha of the 4,561 ha Kelian Protected Forest (site of the former Kelian Mine) and move the remaining wild rhinos there to create a larger protected breeding population. The female rhino (named Najaq) was captured in preparation for this, and was moved to a temporary enclosure with plans to airlift her to the protected forest. However, a few days after her capture, Najaq died from an infection on her leg, believed to be caused by a poacher's
snare trap Animal trapping, or simply trapping or gin, is the use of a device to remotely catch an animal. Animals may be trapped for a variety of purposes, including food, the fur trade, hunting, pest control, and wildlife management. History Neolithic ...
.


In captivity

The Bornean rhinoceros is extremely rare in captivity, with only one individual (female) remaining in captivity at the Borneo Rhinoceros Sanctuary in Sabah. The potential captive breeding of this animals is mostly threatened by the remaining individual being unable to breed. The last male (named Tam) died on May 27, 2019. In February 2014, a decision was made to send Tam to the
Cincinnati Zoo and Botanical Garden The Cincinnati Zoo & Botanical Garden is the sixth oldest zoo in the United States, founded in 1873 and officially opening in 1875. It is located in the Avondale neighborhood of Cincinnati, Ohio. It originally began with in the middle of the c ...
to breed with its female Western Sumatran rhinoceros, Suci. The decision to breed the two subspecies together was made in a last-ditch attempt to save the species as a whole and due to the fact that Puntung and Iman are non-reproductive and Suci's only other breeding option in captivity was her brother. The plan later was canceled due to the death of Suci in March 2014 due to Iron Storage Disease. Puntung fell ill and was euthanized in May 2017, so in late 2018 a new female rhinoceros, named Pahu, was captured for the captive breeding program. Tam died from old age in May 2019, leaving Iman and Pahu as the last surviving captive Bornean rhinoceros. However, Iman also passed in November 2019, leaving the species locally extinct in Malaysian Borneo and leaving Pahu the last Bornean rhinoceros in captivity.


References


External links

{{Taxonbar, from=Q15487139 Rhinoceroses Mammals described in 1965 Mammals of Southeast Asia Mammals of Borneo Mammals of Malaysia Mammals of Indonesia Species endangered by human consumption for medicinal or magical purposes Species endangered by deforestation Species endangered by roadbuilding Species endangered by agricultural development Species endangered by logging for timber