Animal Info - Sumatran Rhinoceros

(Other Names: Asian or Asiatic Two-horned Rhinoceros, Badak Kerban, Badak Sumbu, Hairy Rhinoceros, Rhinocéros de Sumatra, Rinoceronte de Sumatra)

Dicerorhinus sumatrensis (Didermocerus or Rhinoceros s.)

Status: Critically Endangered

Contents

1. Profile (Picture)
2. Tidbits
3. Status and Trends (IUCN Status, Countries Where Currently Found, Population Estimates, History of Distribution, Threats and Reasons for Decline)
4. Data on Biology and Ecology (Size and Weight, Habitat, Age to Maturity, Gestation Period, Birth Season, Birth Rate, Dispersal, Maximum Age, Diet, Behavior (Senses, Activity Patterns, Wallowing, Movement), Social Organization, Density and Range)
5. References

Profile

Pictures: Sumatran Rhino #1 (Huffman 2004); Sumatran Rhino #2 (31 Kb JPEG) (Intl. Rhino Found. 2002); Sumatran Rhino #3 (71 Kb JPEG) (Czech Web Site)

The Sumatran rhino is a two-horned rhino weighing 600 - 950 kg (1,300 - 2,000 lb). It is 1 - 1.5 m (3 - 5') tall at the shoulder. In the wild, the adult Sumatran rhino’s hair is sparse and very short, 1 – 2 cm (0.4 - 0.8") long except on the ear fringes and tail tip (The long shaggy brown hair that develops in zoos is an aberration caused by lack of mud wallows and thick vegetation.). In the wild, these rhinos are usually covered in mud due to their frequent use of mud wallows. This small rhino has relatively few skin wrinkles except around the neck. The skin is 16 mm thick at its thickest part and usually dark gray-brown.  Like other rhinos, the Sumatran rhino has poor vision. 

The Sumatran rhino is found in a wide variety of habitats, from lowland rain forests and swamps to mountain moss forests. It has been reported to prefer hilly areas near water, particularly steep upper valleys with thick undergrowth, as well as secondary forest where the upper canopy is broken and the smaller shrubs and vines on which it feeds are more numerous. Salt licks are an important habitat requirement of the Sumatran rhino.

The Sumatran rhino is a browser. It feeds on a wide variety of vegetation including leaves, twigs, bark, fruit, smaller shrubs, canes and vines. Wild mangoes, bamboo and figs are especially favored. It is fond of salt and visits salt licks regularly. The Sumatran rhino feeds before dawn and after sunset and moves mostly by night. Much of the day is spent in wallows.  The Sumatran rhino makes seasonal movements, staying in hilly country when the lowlands are flooded during the rains, descending when the weather has become cool near the end of the rains, and returning to high ground by March. The Sumatran rhino can ascend and descend steep slopes with great agility. It swims well and has been known to swim in the sea.  Males are usually solitary, while females are found in mother-offspring groups. 

The Sumatran rhino's range formerly extended from Assam (India) and Bangladesh to Myanmar, Cambodia, Laos, Vietnam, Thailand, Peninsular Malaysia, Sumatra (Indonesia) and Borneo (Brunei, Indonesia, and Malaysia). Due to overhunting and habitat loss, it has been reduced to small, scattered populations. In recent times its largest concentrations have been in Sumatra (Indonesia) and the Malay Peninsula (Malaysia). In addition, it is present on Borneo in Sabah (Malaysia) and in small numbers in Myanmar and Thailand, and possibly other locations.

Tidbits

*** The Sumatran rhino is one of the world's rarest mammals.

*** Although the Sumatran rhino avoids areas where the primary forest has been substantially modified by logging, it prefers secondary forest where the upper canopy has been broken and the smaller shrubs, canes and vines on which it feeds are more numerous. For this reason, certain types of logging may actually be beneficial by encouraging this secondary growth.

*** The Sumatran rhino tends to return to favorite spots such as mud wallows and salt licks, and, unfortunately, poachers use this habit to good advantage.

*** The Sumatran rhino is the smallest rhino species.

*** The horn of a rhino perches on a roughened area of the skull (rather than being "rooted" in the skull).

*** Accurate determination of the distribution of Sumatran rhinos in Peninsular Malaysia requires conducting field surveys to confirm reports from inhabitants of the area, because most people confuse rhino tracks with those of the Asian (Malayan) tapir, Tapirus indicus. Many people believe tapirs are actually young rhinos; the base Malayan name (badak) is the same for both animals (Flynn & Abdullah 1984).

Status and Trends

IUCN Status:

Countries Where the Sumatran Rhinoceros Is Currently Found:

2004: Occurs in Indonesia, Malaysia, Myanmar, Thailand and Vietnam. It may be extinct in Cambodia, India, and Laos. (IUCN 2004)

Population Estimates:

[Note: Figures given are for wild populations only.]

History of Distribution:

The detailed distribution of the Sumatran rhino has always been difficult to establish with certainty, probably because it often exists only in small, scattered populations in forested habitat. Up to the end of the 19th century, its range is thought to have generally extended from Assam (India) and Bangladesh to Myanmar, Cambodia, Laos, Vietnam, Thailand, Peninsular Malaysia, Sumatra (Indonesia) and Borneo (Brunei, Indonesia, and Malaysia). From the 1960's through the present, its largest concentrations have been known from Sumatra and the Malay Peninsula. In addition, it has been known to be present on Borneo in Sabah (Malaysia) and in small numbers in Myanmar and Thailand. It was rediscovered in Sarawak (Malaysia) in 1987 after having been thought to be extinct there for forty years. There has been continued speculation that it may still exist in Cambodia and Laos.

Distribution Map (5 Kb JPEG) (Huffman 2004)
Distribution Map (35 Kb JPEG) (Intl. Rhino Found. 2004)

Threats and Reasons for Decline:

The two main reasons for the Sumatran rhino's decline have been poaching for virtually all of the parts of its body (especially the horn), which are believed by some peoples of the Orient to have medicinal purposes, and loss of its forested habitat due to conversion of the land to other uses.  These threats still threaten its future survival. (Caughley & Gunn 1996)

Data on Biology and Ecology

Size and Weight:

The Sumatran rhino weighs 600 - 950 kg (1,300 - 2,000 lb).  It is 1 - 1.5 m (3 - 5') tall at the shoulder and the length of its body is 2 - 3 m (6.5 - 9.5'). (Intl. Rhino Found. 2005) 

Habitat:

The Sumatran rhino can live in a wide variety of habitats, from lowland rain forests and swamps to mountain moss forests. It has been reported to prefer hilly areas near water, particularly steep upper valleys with thick undergrowth, as well as secondary forest where the upper canopy is broken and the smaller shrubs and vines on which it feeds are more numerous. Salt licks are an important habitat requirement of the Sumatran rhino. (Nowak 1999)

The Sumatran rhino lives in both the Sundaland Biodiversity Hotspot (Cons. Intl. 2005) as well as the Peninsular Malaysian Lowland & Montane Forests, Sumatran Montane Forests, and Sumatran-Nicobar Islands Lowland Forests Global 200 Ecoregions. (Olson & Dinerstein 1998, Olson & Dinerstein 1999)

Age to Maturity:

Female Sumatran rhinos become sexually mature at 6 to 7 years of age, males at 10 years (Intl. Rhino Found. 2005).

Gestation Period:

For two baby Sumatran rhinos born in captivity at the Cincinnati Zoo in 2001 and 2004, the gestation periods were 475 and 477 days (Khan et al. 2004).

Birth Season:

The mating season is July - October (Humphrey & Bain 1990).  In northern Sumatra, one study found that most births took place from October - May, the period of heaviest rainfall (Nowak 1999).

Birth Rate:

A single calf is born every 3 years (Intl. Rhino Found. 2005).

Dispersal:

A Sumatran rhino calf leaves its mother after about 18 months, when she gives birth to her next young (Burnie & Wilson 2001).

Maximum Age:

A captive Sumatran rhino lived for 32 years and 8 months (Groves & Kurt 1972).

Diet:

The Sumatran rhino is a browser, similar to the black rhino. It feeds on a wide variety of vegetation including leaves, twigs, bark, fruit, smaller shrubs, canes and vines, with a majority of the plant species being characteristic of disturbed forest or forest edge in some areas, and of primary forest in other areas. Wild mangoes, bamboo and figs are especially favored. It knocks down saplings to feed on leaves and shoots. It is fond of salt and visits salt licks regularly. (Groves & Kurt 1972, Nowak 1999)

Behavior:

Senses: Rhinos have poor vision (Burnie & Wilson 2001).

Activity Patterns: The Sumatran rhino feeds before dawn and after sunset and moves mostly by night. Much of the day is spent in wallows. (Groves & Kurt 1972)

Wallowing: The Sumatran rhino, like all rhinos, hippos, and similar sparsely haired mammals, wallows in mud, which dries onto the skin. (Burnie & Wilson 2001) Wallowing is thought to provide protection against insects, and/or to provide cooling.  Wallows are often rainwater ponds on hilltops which are dug out by the rhinos themselves. They regularly are located in the center of a rhino's territory and are connected by a system of trails.  The surrounding area is cleared of vegetation to a distance of 10 - 35 m (33 - 115') and is used as a resting place. One study gave measurements of wallows as 2 - 4 m (6.6 - 13.1') by 1 - 1.5 m (3.3 - 4.9'); another found them to have a diameter of up to 8 m (26'). (Groves & Kurt 1972)

Movement: The Sumatran rhino makes seasonal movements, staying in hilly country when the lowlands are flooded during the rains, descending when the weather has become cool near the end of the rains, and returning to high ground by March. The Sumatran rhino can ascend and descend steep slopes with great agility. It swims well and has been known to swim in the sea.   The Sumatran rhino is apparently regular in its movements, making well-defined trails to wallows and feeding sites and changing the latter every 10 - 15 days. Males seem to be more nomadic than females. (Groves & Kurt 1972)

Social Organization:

Males are usually solitary, while females are found in mother-offspring groups. The largest group found consisted of three animals. (Groves & Kurt 1972) Females have relatively stable home ranges, which are very large and partially overlapping. In some areas, males are apparently nomadic and wander along stream beds, old game trails, or just cross-country. (Humphrey & Bain 1990) A study in Gunung Leuser National Park in northern Sumatra (Indonesia) found that home ranges of adult males overlapped extensively, but that within them there appeared to be small, exclusive core areas or territories. Female home ranges were smaller than those of males and generally were separate from one another except in the vicinity of salt licks. Females were thought to be territorial and to avoid one another. (Nowak 1999 )

Density and Range:

Density:

  • One study in Peninsular Malaysia produced estimated densities of 1 Sumatran rhino/40 sq km (1 rhino/15 sq mi) in the "high density" area of the Endau-Rompin region and of 1 Sumatran rhino/80 - 120 sq km (1 rhino/31 - 46 sq mi) in the "low density" region (Flynn & Abdullah 1984).
  • A density of 1 Sumatran rhino/10 sq km (1 rhino/3.8 sq mi) was also reported from Peninsular Malaysia (Humphrey & Bain 1990).
  • A study in Gunung Leuser National Park in northern Sumatra, Indonesia, found a density of 13 - 14 Sumatran rhinos/sq km (34 - 36 rhinos/sq mi), probably considerably higher than in localities with fewer salt licks (Nowak 1999).

Home range:

  • One report stated that the home range of a female Sumatran rhino is from 2 - 3.5 km (1.2 - 2.2 mi) in diameter. Home ranges overlap widely and contain several regular feeding areas. (Groves & Kurt 1972)  
  • A study in Gunung Leuser National Park in northern Sumatra (Indonesia) found the home ranges of adult males averaged 30 sq km (11.6 sq mi) and overlapped extensively. Female home ranges were smaller. (Nowak 1999)  

Territory:

  • The females seem to live in territories, each centered on a wallow. The diameter of a territory is some 500 - 700 m (1600 - 2300'). Each is surrounded by feeding grounds, which are visited by several animals. Within the territory is a dense system of tracks leading to and from the wallow, which is usually located on a mountain top or a catchment area of a small stream. (Groves & Kurt 1972)

References

Anon. 1994a, Arkive, Burnie & Wilson 2001, Burton & Pearson 1987, Caughley & Gunn 1996, Choudhury 1997, Cons. Intl. 2005, Cumming et al. 1990, Curry-Lindahl 1972, Czech Web Site, Dulaney 2001, Fitter 1974, Flynn & Abdullah 1984, Focus 2000, Foose & van Strien 1997, Gee 1964, Groves & Kurt 1972, Harrisson 1976, Hislop 1966, Huffman 1999d, Huffman 2004, Humphrey & Bain 1990, Intl. Rhino Found. 2001, Intl. Rhino Found. 2002, Intl. Rhino Found. 2004, Intl. Rhino Found. 2005, IRF 1996, IUCN 1967, IUCN 1994, IUCN 1996, IUCN 2000, IUCN 2003a, IUCN 2004, Khan et al. 2004, Khan et al. 2004a, La Monte & Welch 1934, Macdonald 1984, Morales et al. 1997, Nowak 1999, Nowak & Paradiso 1983, Olson & Dinerstein 1998, Olson & Dinerstein 1999, Oryx 1964b, Oryx 1966d, Oryx 1967c, Oryx 1969b, Oryx 1970b, Oryx 1976d, Oryx 1982b, Oryx 1983b, Oryx 1986f, Oryx 1987b, Rabinowitz 1995, Reilly et al.1997, Shebbeare 1953, WCMC/WWF 1997

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