The Sumatran Rhinoceros (Sumatran Rhino) is the world’s most endangered species of rhinoceros. They are known for their hairy body and double horns, for which they have also got their other names – hairy rhinoceros, woolly (wooly) rhinoceros, and Asian two-horned rhinoceros. They are a rare member of the family Rhinocerotidae, the only extant species of the genus ‘Dicerorhinus’, and one of five extant rhinoceroses. Although they have a large body, nonetheless, they are the smallest among all the rhino species. The Sumatran rhinoceros is an elusive animal, and because of their rarity, the details of its life history are scarce.
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Sumatran Rhinoceros Scientific Classification
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Size: The rhino stands 112–145 cm (3.67–4.76 ft) high at its shoulder, while its head-and-body length is 2.36–3.18 m (7.7–10.4 ft).
Weight: Reportedly, they weigh between 500 and 1,000 kg (1,100 to 2,200 lb), with an average weight of 700–800 kg (1,500–1,800 lb).
Fur/hair/coat: Most of its body is covered with a coat of reddish-brown hair, which often turns black as the animal grows older.
Horns: Like both the African species, this species has two horns, with the larger one being the nasal horn that is typically 15–25 cm (5.9–9.8 in). The posterior horn is typically a stub that may grow up to 3 inches (10 centimeters) in length. However, in most cases, it is generally a hump.
Skin: They have a coarse skin type typical to the rhino species, but it is soft and pliable. The color of the skin is rusty to reddish-brown. They have unique skin folds with two distinct folds in the skin circling the body behind their anterior legs and before the posterior legs. Their neck folds are lesser and so are the folds at the base of their legs. Although, the skin of this species is fairly thin: about 10-16 mm.
Eyes: Their eyes are small with wrinkles around them.
Tail: They have a medium size tail that narrows at the tip. The tail-tip is hairier than the rest of the body. The tail measures to 35–70 cm (14–28 in).
The Sumatran rhino lives for 30 to 45 years, which is almost the same like most other rhino species.
While their historic range was throughout Myanmar (Burma), Thailand, Malaysia and the Indonesian islands of Sumatra and Borneo, and rarely in Northeast India, presently, these rhinos are found in several scattered National Parks in Malaysia, Sumatra, Indonesia, and Borneo, including Bukit Barisan Selatan, Gunung Leuser, Way Kambas, Taman Negara & Tabin Wildlife reserve.
Habitat: Where do Sumatran Rhinos live
The Sumatran rhinos are scattered throughout the tropical bush lands, the grasslands, and the savannas. The species occurs mostly in the mountainous regions nearby water sources.
Classification of Species
- The Western Sumatran Rhinoceros (Dicerorhinus sumatrensis sumatrensis): This subspecies is the commonest of the 3 Researchers estimated that there are around 275 of these individuals living in western Sumatra. This variety has a slight genetic difference with the Eastern variety.
- The Eastern Sumatran Rhinoceros (Dicerorhinus sumatrensis harrissoni) or, Bornean Rhinoceros: These animals were common throughout Borneo, however, presently it is estimated that there are less than even 50 survivors.
- The Northern Sumatran Rhinoceros (Dicerorhinus sumatrensis lasiotis): Unfortunately, this subspecies has been declared extinct. The individuals were rare, and roamed in the forests of NE India and Northern Bangladesh. Although, unconfirmed reports suggest that, there is a small population left in Burma.
Behavior and Lifestyle
The Sumatran rhinos are shy. They usually live in the deep greens living a solitary life, except during mating season or while raising the young. Despite being heavy creatures, they have the ability to run fast.
They are territorial. The bulls (males) have territories of approximately 50 square kilometers, while the females have smaller territories of around 10-15 square kilometer. They usually mark their territories by leaving excrement, scraping the soil with their feet, and bending saplings into distinctive patterns.
These creatures mostly feed in the morning or around dusk and spend much time in wallowing all day. They exhibit seasonal movements, and move uphill during lowland floods, and come back again to the lowlands in the dry season. During summer, they would often dig or deepen their own pool of mud and remain in the muddy water.
Surprisingly, the Sumatran rhinos are vocal and use a variety of sounds to communicate amongst themselves. They mostly emit whistling or whining noises during interaction.
Diet: What Do Sumatran Rhinos Eat
The rhinoceros is herbivorous. They generally live on fruits, leaves, twigs, bamboos, and barks. Sometimes they also consume crops. But this species is usually a browser and opportunistic feeder that would thrive in a wide variety of diet. Dung tests made by researchers have shown that they feast upon more than one hundred species of plants.
Mating and Reproduction
The male rhino reaches its sexual maturity by age seven years, while the females attain puberty much faster at 4. Often, the young Sumatran males are quite aggressive towards the females. They are known to either injure or kill them during mating and courtship.
While studying sexual behavior in captivity, it has also been noticed that, the common signs of estrus in these creatures is the increase in frequency of spraying urine, tail lifting or dangling, and physical contacts with the anus and the genitals. During intercourse, the males exclusively exhibit mounting behavior common in most other mammals.
The female gives birth to a calf every 4 to 5 years, after a gestation period of approximately 15-16 months.
Life Cycle of the baby Sumatran Rhino
Most births of the baby rhinos take place during the period of heaviest rainfall, between October and May. The calves are often attacked by wild dogs or tigers and they will continue staying with the mother until they are 16 to 17 months old. The baby Sumatran rhinos are born with a dense covering of body hair that turns copper brown in young adults.
- They can easily break through the densest vegetation using their horns and rims of hard skin and cartilage on nose and head.
- For defensive purposes, the Sumatran rhinos are agile and can run fast, reaching speeds of up to 40 km/h (25 m/h).
- Because they live in hilly regions, they can climb hills very easily, managing their ways through steep slopes and riverbanks.
- The wallowing behavior of the Sumatran rhino is thought to either cool itself or to protect itself from insects.
- When the rhino comes across a stack of dung (of another rhino), it would excrete and scratch its hind feet in its own dung to mark its territory, and kick it around in the bushes for marking its feet and the surrounding tracks with the scent of the feces. This is a behavioral adaptation.
- The Sumatran rhinoceros’ ears possess a wide rotational range for detection of sounds, and their olfactory has an excellent ability to detect smells to alert instantly to the presence of predators.
Owing to their large size, the Sumatran rhino has no known predators other than the humans. However, as mentioned, the calves are vulnerable to the large cats like tigers and wild dogs.
The present population of the Sumatran rhino is estimated to be around 275. Their numbers have got halved over the last few years. However, this decline in their population appears to have slowed, with the count is seemingly stabilizing in most of the core areas.
The Sumatran rhino is a critically endangered species. The IUCN 3.1 has categorized them under the ‘CR’ (Critically Endangered) species list.
- The Sumatran rhino is the oldest of all living mammals in the whole world.
- The heaviest recorded Sumatran rhino was 2,000 kg (4,400 lb).
- These herbivores tend to spend the sunny days sitting in pond or mud and wallows to keep themselves cool.
- The total population in captivity is less than ten In the past two centuries to 1998, there had been around 96 of these rhinos in zoos and circuses.
- These creatures are possibly extinct in Myanmar.
- The rhino can easily break through the densest vegetation, leaving round tunnels.
- Other than the Indian rhino, only the Sumatran rhinos have canine teeth. The other five species have three premolars and three molar teeth on each side of their upper and lower jaws.
- The biggest threat to the existence of the Sumatran rhino is its habitat loss and poaching. The horns of these animals are in high demand in the world’s black market, especially in China for medicinal purposes. Their horns are also valued in the Middle East (especially Yemen), and North Africa as an ornamental dagger handle.