Sumatran Rhinoceros (Dicerorhinus sumatrensis)
This species is now extinct in Thailand
The Sumatran rhinoceros (Dicerorhinus sumatrensis) is a
member of the family Rhinocerotidae and one of five extant rhinoceroses. It is
the only extant species of the genus Dicerorhinus. It is the smallest
rhinoceros, although is still a large mammal. This rhino stands 112145 cm
(3.674.76 ft) high at the shoulder, with a head-and-body length of 2.363.18 m
(7.710.4 ft) and a tail of 3570 cm (1428 in). The weight is reported to range
from 500 to 1,000 kg (1,100 to 2,200 lb), averaging 700800 kg (1,5001,800 lb),
although there is a single record of a 2,000 kg (4,400 lb) specimen. Like the
African species, it has two horns; the larger is the nasal horn, typically 1525
centimetres (5.99.8 in), while the other horn is typically a stub. A coat of
reddish-brown hair covers most of the Sumatran rhino's body.
Members of the species once inhabited rainforests, swamps and cloud forests in India, Bhutan, Bangladesh, Myanmar, Laos, Thailand, Malaysia, Indonesia, and China. In historical times they lived in southwest China, particularly in Sichuan. They are now critically endangered, with only six substantial populations in the wild: four on Sumatra, one on Borneo, and one in the Malay Peninsula. Their numbers are difficult to determine because they are solitary animals that are widely scattered across their range, but they are estimated to number fewer than 275 Survival of the Peninsular Malaysia population is in doubt, and one of the Sumatran populations may already be extinct. Total numbers today may be as low as 200. The decline in the number of Sumatran rhinoceros is attributed primarily to poaching for their horns, which are highly valued in traditional Chinese medicine, fetching as much as US$30,000 per kilogram on the black market. The Sumatran rhino is a mostly solitary animal except for courtship and offspring-rearing. It is the most vocal rhino species and also communicates through marking soil with its feet, twisting saplings into patterns, and leaving excrement. The species is much better studied than the similarly reclusive Javan rhinoceros, in part because of a program that brought 40 Sumatran rhinos into captivity with the goal of preserving the species. The program was considered a disaster even by its initiator; most of the rhinos died and no offspring were produced for nearly 20 years, representing an even worse population decline than in the wild.
Taxonomy and naming
The first documented Sumatran rhinoceros was shot 16 kilometres (9.9 mi) outside Fort Marlborough, near the west coast of Sumatra, in 1793. Drawings of the animal, and a written description, were sent to the naturalist Joseph Banks, then president of the Royal Society of London, who published a paper on the specimen that year. It was not until 1814, however, that the species was given a scientific name, by Johann Fischer von Waldheim, a German scientist and curator of the State Darwin Museum in Moscow, Russia.
The scientific name Dicerorhinus sumatrensis comes from the Greek terms di (δι, meaning "two"), cero (κέρας, meaning "horn"), and rhinos (ρινος, meaning "nose"). Sumatrensis signifies "of Sumatra", the Indonesian island where the rhinos were first discovered. Carolus Linnaeus originally classified all rhinos in the genus Rhinoceros; therefore the species was originally identified as Rhinoceros sumatrensis. Joshua Brookes considered the Sumatran rhinoceros, with its two horns, a distinct genus from the one-horned Rhinoceros, and gave it the name Didermocerus in 1828. Constantin Wilhelm Lambert Gloger proposed the name Dicerorhinus in 1841. In 1868, John Edward Gray proposed the name Ceratorhinus. Normally the oldest name would be used, but a 1977 ruling by the International Commission on Zoological Nomenclature established the proper genus name as Dicerorhinus.
The three subspecies are:
D. s. sumatrensis, known as the western Sumatran rhinoceros, has only 170 to 230 rhinos remaining, mostly in the national parks of Bukit Barisan Selatan and Gunung Leuser in Sumatra. Around 75 may also live in Peninsular Malaysia. The main threats against this subspecies are habitat loss and illegal poaching. There is a slight genetic difference between the western and eastern Sumatran rhinos. The rhinos in Peninsular Malaysia were once known as D. s. niger, but were later recognized to be similar to the rhinos on western Sumatra.
D. s. harrissoni, known as the eastern Sumatran rhinoceros or Bornean rhinoceros, was once common throughout Borneo; now only about 50 individuals are estimated to survive. The known population on Borneo lives in Sabah. There are unconfirmed reports of animals surviving in Sarawak and Kalimantan. This subspecies is named after Tom Harrisson, who worked extensively with Bornean zoology and anthropology in the 1960s. The Bornean subspecies is markedly smaller than the other two.
D. s. lasiotis, known as the northern Sumatran rhinoceros, once roamed in India and Bangladesh, but has been declared extinct in these countries. Unconfirmed reports suggest there may be a small population still surviving in Burma, but the political situation in the country has prevented verification. The name lasiotis is derived from the Greek for "hairy-ears". Later studies showed their ear-hair was not longer than other Sumatran rhinos, but D. s. lasiotis remained a subspecies because it was significantly larger than the other subspecies.
Ancestral rhinoceroses first diverged from other
perissodactyls in the Early Eocene. Mitochondrial DNA comparison suggests the
ancestors of modern rhinos split from the ancestors of Equidae around 50 million
years ago. The extant family, the Rhinocerotidae, first appeared in the Late
Eocene in Eurasia, and the ancestors of the extant rhino species dispersed from
Asia beginning in the Miocene
The Sumatran rhinoceros is considered the least derived of the extant species, as it shares more traits with its Miocene ancestors. Paleontological evidence in the fossil record dates the genus Dicerorhinus to the Early Miocene, 2316 million years ago. Many fossils have been classified as members of Dicerorhinus, but no other recent species are in the genus. Molecular dating suggests a split of Dicerorhinus from the four other extant species as far back as 25.9 ± 1.9 million years. Three hypotheses have been proposed for the relationship between the Sumatran rhinoceros and the other living species. One hypothesis suggests the Sumatran rhinoceros is closely related to the black and white rhinos in Africa, evidenced by the species having two horns, instead of one. Other taxonomists regard the Sumatran rhinoceros as a sister taxon of the Indian and Javan rhinoceros because their ranges overlap so closely. A third hypothesis, based on more recent analyses, however, suggests the two African rhinos, the two Asian rhinos and The Sumatran rhinoceros represent three essentially separate lineages that split around 25.9 million years ago, and it may therefore be unclear which group diverged first. Because of morphological similarities, the Sumatran rhinoceros is believed to be closely related to the extinct woolly rhinoceros (Coelodonta antiquitatis). The woolly rhinoceros, so named for the coat of hair it shares with the Sumatran rhinoceros, first appeared in China, and by the Upper Pleistocene, ranged across the Eurasian continent from Korea to Spain. The woolly rhinoceros survived the last Ice Age, but like the woolly mammoth, most or all became extinct around 10,000 years ago. Although some morphological studies questioned the relationship, recent molecular analysis has supported the two species as sister taxa.A mature Sumatran rhino stands about 120145 centimetres (3.94.76 ft) high at the shoulder, has a body length of around 250 centimetres (8.2 ft) and weighs 500800 kilograms (1,1001,800 lb), though the largest individuals in zoos have been known to weigh as much as 1,000 kilograms (2,200 lb). Like the African species, it has two horns. The larger is the nasal horn, typically only 1525 centimetres (5.99.8 in), though the longest recorded specimen was much longer at 81 centimetres (32 in). The posterior horn is much smaller, usually less than 10 centimetres (3.9 in) long, and often little more than a knob. The larger nasal horn is also known as the anterior horn; the smaller posterior horn as the frontal horn. The horns are dark gray or black in colour. The males have larger horns than the females, though the species is not otherwise sexually dimorphic. The Sumatran rhino lives an estimated 3045 years in the wild, while the record time in captivity is a female D. lasiotis which lived for 32 years and 8 months before dying in the London Zoo in 1900. Two thick folds of skin encircle the body behind the front legs and before the hind legs. The rhino has a smaller fold of skin around its neck. The skin itself is thin, 1016 millimetres (0.390.63 in), and in the wild the rhino appears to have no subcutaneous fat. Hair can range from dense (the most dense hair in young calves) to scarce and is usually a reddish-brown. In the wild, this hair is hard to observe because the rhinos are often covered in mud. In captivity, however, the hair grows out and becomes much shaggier, likely because of less abrasion from walking through vegetation. The rhino has a patch of long hair around the ears and a thick clump of hair at the end of the tail. Like all rhinos, they have very poor vision. The Sumatran rhinoceros is fast and agile; it climbs mountains easily and comfortably traverses steep slopes and riverbanks. Genetic analysis of Sumatran rhino populations has identified three distinct genetic lineages. The channel between Sumatra and Malaysia was not as significant a barrier for the rhinos as the Barisan Mountains along the length of Sumatra, for rhinos in eastern Sumatra and Peninsular Malaysia are more closely related than the rhinos on the other side of the mountains in western Sumatra. In fact, the eastern Sumatra and Malaysia rhinos show so little genetic variance that the populations were likely not separate during the Pleistocene, when sea levels were much lower and Sumatra formed part of the mainland. Both populations of Sumatra and Malaysia, however, are close enough genetically that interbreeding would not be problematic. The rhinos of Borneo are sufficiently distinct that conservation geneticists have advised against crossing their lineages with the other populations. Conservation geneticists have recently begun to study the diversity of the gene pool within these populations by identifying micro satellite loci. The results of initial testing found levels of variability within Sumatran rhino populations comparable to those in the population of the less endangered African rhinos, but the genetic diversity of Sumatran rhinos is an area of continuing study. Sumatran rhinoceroses are solitary creatures except for pairing before mating and during offspring rearing. Individuals have home ranges; bulls have territories as large as 50 km2 (19 sq mi), whereas females' ranges are 1015 km2 (3.95.8 sq mi). The ranges of females appear to be spaced apart; males' ranges often overlap. There is no evidence Sumatran rhinos defend their territory through fighting. Marking their territory is done by scraping soil with their feet, bending saplings into distinctive patterns, and leaving excrement. The Sumatran rhino is usually most active when eating, at dawn, and just after dusk. During the day, the rhino wallows in mud baths to cool down and rest. In the rainy season, they move to higher elevations; in the cooler months, they return to lower areas in their range. The rhino spends a large part of its day in wallows. When mud holes are unavailable, the rhino will deepen puddles with its feet and horns. The wallowing behaviour helps the rhino maintain its body temperature and protect its skin from ectoparasites and other insects. Captive specimens, deprived of adequate wallowing, have quickly developed broken and inflamed skins, suppurations, eye problems, inflamed nails, hair loss and have eventually died. One 20-month study of wallowing behavior found they will visit no more than three wallows at any given time. After two to 12 weeks using a particular wallow, the rhino will abandon it. Typically, the rhino will wallow around midday for two to three hours at a time before venturing out for food. Although in zoos the Sumatran rhino has been observed wallowing less than 45 minutes a day, the study of wild animals found 80300 minutes (an average of 166 minutes) per day spent in wallows.
There has been little opportunity to study epidemiology in the Sumatran rhinoceros. Ticks and gyrostigma were reported to cause deaths in captive animals in the 19th century. The rhino is also known to be vulnerable to the blood disease surra, which can be spread by horse-flies carrying parasitic trypanosomes; in 2004, all five rhinos at the Sumatran Rhinoceros Conservation Centre died over an 18-day period after becoming infected by the disease. The Sumatran rhino has no known predators other than humans. Tigers and wild dogs may be capable of killing a calf, but calves stay close to their mothers, and the frequency of such killings is unknown. Although the rhino's range overlaps with elephants and tapirs, the species do not appear to compete for food or habitat. Elephants (Elephas maximus) and Sumatran rhinos are even known to share trails, and many smaller species such as deer, boar and wild dogs will use the trails the rhinos and elephants create.
The Sumatran rhino maintains trails across its range. The trails fall into two types. Main trails will be used by generations of rhinos to travel between important areas in the rhino's range, such as between salt licks, or in corridors through inhospitable terrain that separates ranges. In feeding areas, the rhinos will make smaller trails, still covered by vegetation, to areas containing food the rhino eats. Sumatran rhino trails have been found that cross rivers deeper than 1.5 meters (5 ft) and about 50 meters (165 ft) across. The currents of these rivers are known to be strong, but the rhino is a strong swimmer. A relative absence of wallows near rivers in the range of the Sumatran rhinoceros indicates they may occasionally bathe in rivers in lieu of wallowing. The Sumatran rhino eats a wide range of plants, such as: Mallotus, mangosteens, Ardisia, and Eugenia. Most feeding occurs just before nightfall and in the morning. The Sumatran rhino is a browser, with a diet of young saplings, leaves, fruits, twigs and shoots. The rhinos usually consume up to 50 kg (110 lb) of food a day. Primarily by measuring dung samples, researchers have identified more than 100 food species consumed by the Sumatran rhinoceros. The largest portion of the diet is tree saplings with a trunk diameter of 16 cm (0.42.4 inches). The rhinoceros typically pushes these saplings over with its body, walking over the sapling without stepping on it, to eat the leaves. Many of the plant species the rhino consumes exist in only small portions, which indicates the rhino is frequently changing its diet and feeding in different locations. Among the most common plants the rhino eats are many species from the Euphorbiaceae, Rubiaceae and Melastomataceae families. The most common species the rhino consumes is Eugenia. The vegetal diet of the Sumatran rhinoceros is high in fiber and only moderate in protein. Salt licks are very important to the nutrition of the rhino. These licks can be small hot springs, seepages of salty water or mud-volcanoes. The salt licks also serve an important social purpose for the rhinosmales visit the licks to pick up the scent of females in oestrus. Some Sumatran rhinos, however, live in areas where salt licks are not readily available, or the rhinos have not been observed using the licks. These rhinos may get their necessary mineral requirements by consuming plants rich in minerals.
The Sumatran rhinoceros is the most vocal of the rhinoceros species. Observations of the species in zoos show the animal almost constantly vocalizing, and it is known to do so in the wild, as well The rhino makes three distinct noises: eeps, whales, and whistle-blows. The eep, a short, one-second-long yelp, is the most common sound. The whale, named for its similarity to vocalizations of the humpback whale is the most song-like vocalization and the second-most common. The whale varies in pitch and lasts from four to seven seconds. The whistle-blow is named because it consists of a two-second-long whistling noise and a burst of air in immediate succession. The whistle-blow is the loudest of the vocalizations, loud enough to make the iron bars in the zoo enclosure where the rhinos were studied vibrate. The purpose of the vocalizations is unknown, though they are theorized to convey danger, sexual readiness, and location, as do other ungulate vocalizations. The whistle-blow could be heard at a great distance, even in the dense brush in which the Sumatran rhino lives. A vocalization of similar volume from elephants has been shown to carry 9.8 km (6.1 mi) and thus the whistle-blow may carry as far. The Sumatran rhinoceros will sometimes twist the saplings they do not eat. This twisting behavior is believed to be used as a form of communication, frequently indicating a junction in a trail.
Females become sexually mature at the age of six to seven
years, while males become sexually mature at about 10 years old. The gestation
period is around 1516 months. The calf, which typically weighs 4060 kg (88132
lb), is weaned after about 15 months and stays with the mother for the first two
to three years of its life. In the wild, the birth interval for this species is
estimated to be four to five years; its natural offspring-rearing behavior is
unstudied. The reproductive habits of the Sumatran rhinoceros have been studied
in captivity. Sexual relationships begin with a courtship period characterized
by increased vocalization, tail raising, urination and increased physical
contact, with both male and female using their snouts to bump the other in the
head and genitals. The pattern of courtship is most similar to that of the black
rhinoceros. Young Sumatran rhino males are often too aggressive with females,
sometimes injuring and even killing them during the courtship. In the wild, the
female could run away from an overly aggressive male, but in their smaller
captive enclosures, they cannot; this inability to escape aggressive males may
partly contribute to the low success rate of captive breeding programs. The
period of oestrus itself, when the female is receptive to the male, lasts about
24 hours, and observations have placed its recurrence between 2125 days. Rhinos
in the Cincinnati Zoo have been observed copulating for 3050 minutes, similar
in length to other rhinos; observations at the Sumatran rhinoceros Conservation
Centre in Malaysia have shown a briefer copulation cycle. As the Cincinnati Zoo
has had successful pregnancies, and other rhinos also have lengthy copulatory
periods, a lengthy rut may be the natural behavior. Though researchers observed
successful conceptions, all these pregnancies ended in failure for a variety of
reasons until the first successful captive birth in 2001; studies of these
failures at the Cincinnati Zoo discovered the Sumatran rhino's ovulation is
induced by mating and it had unpredictable progesterone levels. Breeding success
was finally achieved in 2001, 2004 and 2007 by providing a pregnant rhino with
supplementary progestin. Recently, a calf was born in captivity of an endangered
female in western Indonesia, only fifth such birth in one and a quarter century.
Aside from those few individuals kept in zoos and pictured in books, the
Sumatran rhinoceros has remained little known, overshadowed by the more common
Indian, black and white rhinos. Recently, however, video footage of the Sumatran
rhinoceros in its native habitat and in breeding centres has been featured in
several nature documentaries. Extensive footage can be found in an Asia
Geographic documentary The Littlest Rhino. Natural History New Zealand showed
footage of a Sumatran rhino, shot by freelance Indonesian-based cameraman Alain
Compost, in the 2001 documentary The Forgotten Rhino, which featured mainly
Javan and Indian rhinos. Though documented by droppings and tracks, pictures of
the Bornean rhinoceros were first taken and widely distributed by modern
conservationists in April 2006, when camera traps photographed a healthy adult
in the jungles of Sabah in Malaysian Borneo. On April 24, 2007 it was
announced that cameras had captured the first-ever video footage of a wild
Bornean rhino. The night-time footage showed the rhino eating, peering through
jungle foliage, and sniffing the film equipment. The World Wildlife Fund, which
took the video, has used it in efforts to convince local governments to turn the
area into a rhino conservation zone. Monitoring has continued; 50 new cameras
have been set up, and in February 2010, what appeared to be a pregnant rhino was
filmed. A number of folk tales about the Sumatran rhino were collected by
colonial naturalists and hunters from the mid-19th century to early 20th
century. In Burma, the belief was once widespread that the Sumatran rhino ate
fire. Tales described the fire-eating rhino following smoke to its source,
especially campfires, and then attacking the camp. There was also a Burmese
belief that the best time to hunt was every July, when the Sumatran rhinos would
congregate beneath the full moon. In Malaya, it was said that the rhino's horn
was hollow and could be used as a sort of hose for breathing air and squirting
water. In Malaya and Sumatra, it was once believed that the rhino shed its horn
every year and buried it under the ground. In Borneo, the rhino was said to have
a strange carnivorous practice: after defecating in a stream, it would turn
around and eat fish that had been stupefied by the excrement. The species
inhabits tropical rainforest and montane moss forest, and occasionally occurs at
forest margins and in secondary forest (Nowak, 1999). The species occurs mainly
in hilly areas nearby water sources, and exhibits seasonal movements, moving
uphill in times of lowland flooding (van Strien, 1975). This shy species is
dependent on salt licks, and occurs mostly in primary forest in protected areas,
but wandering into secondary forests outside protected areas, especially in the
dry season in search of water (Van Strien, 1975; Boeadi pers. comm.). Males are
primarily solitary, but can have overlapping territories with females, which are
commonly found with offspring (Nowak, 1999). The home range size of females is
probably no more than 500 ha, while males wonder over larger areas, with likely
limited dispersal distance. The species is generally solitary, except for mating
pairs and mothers with young (Nowak, 1999). Its life history characteristics are
not well known, with longevity estimated at about 35-40 years, gestation length
of approximately 15-16 months, and age at sexual maturity estimated at 6-7 years
for females and 10 years for males (Nowak, 1999; IRF website (www.rhinos-irf.org),
2007). Home range: Males up to 5,000 ha, females 1,000 -1,500 ha. Daily
movements between feeding sites and wallows are probably only a few kilometres
per day. Longer treks are made when males and females go to saltlicks (5-10 km)
and by males exploring their large ranges. Dispersal appears to be mainly by
sub-adult animals (4-7 years) old. In this period they may be found rather far
from the home grounds. Adults are very traditional in the use of their ranges
and will not move away unless severely disturbed. Water is never very far away
in the habitats occupied by the Sumatran rhino.
The Taman Negara National Park contains the only known concentrated population of Sumatran rhinoceros on mainland Asia.
The Sumatran rhinoceros lives in both lowland and highland secondary rainforest, swamps and cloud forests. It inhabits hilly areas close to water, particularly steep upper valleys with a lot of undergrowth. The Sumatran rhinoceros once inhabited a continuous range as far north as Burma, eastern India and Bangladesh. Unconfirmed reports also placed it in Cambodia, Laos and Vietnam. All known living animals occur in Peninsular Malaysia, the island of Sumatra and Sabah, Borneo. Some conservationists hope Sumatran rhinos may still survive in Burma, though it is considered unlikely. Political turmoil in Burma has prevented any assessment or study of possible survivors. The last reports of stray animals from Indian limits were in 1990s. The Sumatran rhino is widely scattered across its range, much more so than the other Asian rhinos, which has made it difficult for conservationists to protect members of the species effectively. Only six areas are known to contain communities of more than a handful of Sumatran rhinoceros: Bukit Barisan Selatan National Park, Gunung Leuser National Park, and Way Kambas National Park on Sumatra; Taman Negara National Park in Peninsular Malaysia; and the Tabin Wildlife Reserve in Sabah, Malaysia on the island of Borneo. The Kerinci Seblat National Park, Sumatra's largest, was estimated to contain a population of around 500 rhinos in the 1980s, but due to poaching, this population is now considered extinct. The survival of any animals in Peninsula Malaysia is also in doubt. Population: The total population is estimated at fewer than 275 individuals, though probably more than 220. Until the early 1990's the numbers continued to decline at a rapid rate with estimated losses of 50% or more of the population per decade (Foose and van Strien 1997). Over the last decade the decrease has been halted or slowed in most of the larger populations because of better protection, but animals are still being lost in the small remnant populations. The subspecies Dicerorhinus sumatrensis sumatrensis now occurs mainly on Sumatra, where there are 170 to 230 individuals. It has its largest populations remaining in Bukit Barisan Selata, Way Kambas, and Gunung Leuser National Park (Foose et al., 1997). There are about 60 to 80 animals in Gunung Leuser, about 60 to 80 Bukit Barisan Selatan, and 15-25 in Way Kambas, with some local reports of rhinos occurring outside of protected areas in Aceh Province (Sectionov and Waladi pers. comm.). There are also a few small, non-viable populations, including no more than a few individuals in Kerinci-Seblat National Park. Some populations are decreasing due to poaching, with very steep decreases in some areas (Sectionov and Waladi pers. comm.). Poaching has ceased in Bukit Barisan Selata and Way Kambas National Parks recently (Sectionov and Waladi pers. comm.). Populations in Peninsular Malaysia are now very small, but the species possibly survives in Taman Negara National Park and in Tamon Besor/Belum area. It probably no longer survives in Endau Rompin National Park (Malaysia).
The majority of the few remaining individuals of the subspecies Dicerorhinus sumatrensis harrissoni occur in Tabin National Park in Sabah (Malaysia), with some also in the Danum Valley (also in Sabah). The total population in Sabah is likely to be about 50 individuals (Han pers. comm.). A two year survey from 2000-2002 indicated 6 known individuals, 10 probable individuals, and an additional 35 possible (Van Strien, 2005). The population status of the subspecies Dicerorhinus sumatrensis lasiotis is unknown, with the very slight possibility that a small number of individuals survive in the Lassai Tract in Myanmar. There are over 20 animals in captivity, mostly in Indonesia and Malaysia, with a few in the United States.
Population Trend: Decreasing
Sumatran rhinoceroses were once quite numerous throughout
Southeast Asia. It is now estimated that fewer than 275 individuals remain. The
species is classed as critically endangered, primarily due to illegal poaching.
Until the early 1990s, the population decline was estimated at more than 50% per
decade, and the small, scattered populations now face high risks of inbreeding
depression. Most remaining habitat is in relatively inaccessible mountainous
areas of Indonesia. Poaching of Sumatran rhinoceros is a cause for concern, as
the price of its horn has been estimated as high as $30,000 per kilogram. This
species has been over hunted for many centuries, leading to the current greatly
reduced and still declining population. The rhinos are difficult to observe
and hunt directly (one field researcher spent seven weeks in a tree hide near a
salt lick without ever observing a rhino directly), so poachers make use of
spear traps and pit traps. In the 1970s, uses of the rhinoceros's body parts
among the local people of Sumatra were documented, such as the use of rhino
horns in amulets and a folk-belief that the horns offer some protection against
poison. Dried rhinoceros meat was used as medicine for diarrhoea, leprosy and
tuberculosis. "Rhino-oil", a concoction made from leaving a rhino's skull in
coconut oil for several weeks, may be used to treat skin diseases. The extent of
use and belief in these practices is not known. It was once believed that
rhinoceros horn was widely used as an aphrodisiac; in fact traditional Chinese
medicine never used it for this purpose. Nevertheless, hunting in this species
has primarily been driven by a demand for rhino horns with supposedly medicinal
The rainforests of Indonesia and Malaysia, which the Sumatran rhino inhabits, are also targets for legal and illegal logging because of the desirability of their hardwoods. Rare woods like merbau, meranti and semaram are valuable on the international markets, fetching as much as $1,800 per m3 ($1,375 per cu yd). Enforcement of illegal-logging laws is difficult because humans live within or near many of the same forests as the rhino. The 2004 Indian Ocean earthquake has been used to justify new logging. Although the hardwoods in the rainforests of the Sumatran rhino are destined for international markets and not widely used in domestic construction, the number of logging permits for these woods has increased dramatically because of the tsunami. However, while it has been suggested that this species is highly sensible to habitat disturbance, it appears this is of little importance compared to hunting, as it can withstand more or less any forest condition.
The species has been included on CITES Appendix I since 1975, and legally protected in all range states. An extensive international co-operative programme for the conservation of this species is being implemented with in situ activities being conducted in Indonesia and Malaysia. The primary objectives are to develop and deploy effective anti-poaching teams and to provide the co-ordination capacity to manage and sustain the programme. Rhino Protection Units (RPU) have been a force majeur in stopping poaching in Sumatra. Many organizations are involved with these units, including the Government of Indonesia (Sectionov and Waladi pers. comm.). The expansion and reinforcement of anti-poaching programmes is the top priority if this species is to survive. There are also ongoing efforts to develop managed breeding centres for the species in Indonesia and Malaysia. There have been recent advances in captive breeding techniques for this species, including a successful births at the Cincinnati Zoo in 2001 and 2004 (Khan et al., 2004). One of these offspring was transferred back to a breeding centre in Sumatra. There is a need for further surveys in northern Myanmar to determine the status of any remaining populations.