Indian Rhinoceros

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Indian Rhinoceros
Indian rhinoceros (from left to right: infant male, adult female, and juvenile female)
Indian rhinoceros (from left to right: infant male, adult female, and juvenile female)
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Perissodactyla
Family: Rhinocerotidae
Genus: Rhinoceros
Species: R. unicornis
Binomial name
Rhinoceros unicornis
(Linnaeus, 1758)
Indian Rhinoceros range
Indian Rhinoceros range

The Indian Rhinoceros or the Great One-horned Rhinoceros or the Asian One-horned Rhinoceros (Rhinoceros unicornis) is a large mammal found in Nepal and in Assam, India. It is confined to the tall grasslands and forests in the foothills of the Himalayas. The Indian Rhinoceros can run at speeds of up to 25 mph for short periods of time and is also an excellent swimmer. It has an excellent sense of hearing and smell but relatively poor eyesight.

Contents

[edit] Taxonomy

The Indian Rhinoceros was the first rhinoceros known to Europeans. Rhinoceros from the Greek, "rhino" meaning nose and "ceros" meaning horn. Unicornis is from the Latin, "uni" meaning one and "cornis" also meaning horn. The Indian Rhinoceros is monotypic, meaning there are no distinct subspecies. Rhinoceros unicornis was the type species for the rhinoceros family, first classified by Carolus Linnaeus in 1758.[2]

[edit] Evolution

Main article: Rhinoceros#Evolution

Ancestral rhinoceroses first diverged from other Perissodactyls in the Early Eocene. Mitochondrial DNA comparison suggests that the ancestors of modern rhinos split from the ancestors of Equidae around 50 million years ago.[3] 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.[4]

Fossils of Rhinoceros unicornis appear in the Middle Pleistocene. In the Pleistocene, the Rhinoceros genus ranged throughout Southeast Asia and South Asia, with specimens located on Sri Lanka. Into the Holocene, some rhinoceros lived as far west as Gujarat and Pakistan until as recently as 3,200 years ago.[2]

The Indian and Javan Rhinoceros, the only members of the genus Rhinoceros, first appear in the fossil record in Asia around 1.6 million–3.3 million years ago. Molecular estimates, however, suggest the species may have diverged much earlier, around 11.7 million years ago.[5][3] Although belonging to the type genus, the Indian and Javan Rhinoceros are not believed to be closely related to other rhino species. Different studies have hypothesized that they may be closely related to the extinct Gaindetherium or Punjabitherium. A detailed cladistic analysis of the Rhinocerotidae placed Rhinoceros and the extinct Punjabitherium in a clade with Dicerorhinus, the Sumatran Rhino. Other studies have suggested the Sumatran Rhinoceros is more closely related to the two African species.[6] The Sumatran Rhino may have diverged from the other Asian rhinos as far back as 15 million years ago.[4][7]

[edit] Description

Indian Rhino at the Metro Toronto Zoo.
Indian Rhino at the Metro Toronto Zoo.

In size it is equal to that of the white rhino in Africa. Not including the white rhino, it is the largest of all rhinos, and probably the one with the best armor, along with the Javan rhino's armor. Fully grown males are larger than females in the wild, weighing from 2200- 3000 kg (4,800 - 6,600 lb). Female Indian rhinos weigh about 1600 kg. The Indian Rhino is from 5.7 to 6.7 feet tall and can be up to 13 feet long. The record-sized specimen of this rhino was approximately 3500 kg.

The Great One-Horned Rhinoceros has a single horn; this is present in both males and females, but not on newborn young. The horn, like human fingernails, is pure keratin and starts to show after about 6 years. In most adults the horn reaches a length of about 25 centimeters,[8] but have been recorded up to 57.2 centimeters in length. The nasal horn curves backwards from the nose. Its horn is naturally black. In captive animals, the horn is frequently worn down to a thick knob.[2]

Indian Rhino at the Metro Toronto Zoo.
Indian Rhino at the Metro Toronto Zoo.

This prehistoric-looking rhinoceros has thick, silver-brown skin which becomes pinkish near the large skin folds that cover its body. Males develop thick neck-folds. Its upper legs and shoulders are covered in wart-like bumps. It has very little body hair, aside from eyelashes, ear-fringes and tail-brush.[2]

In captivity, four are known to have lived over 40 years, the oldest living to be 47.[2]

[edit] Behavior

Moghul emperor Babur on a rhino hunt
Moghul emperor Babur on a rhino hunt

These rhinos live in tall grasslands and riverine forests, but due to habitat loss they have been forced into more cultivated land. They are mostly solitary creatures, with the exception of mothers and calves and breeding pairs, although they sometimes congregate at bathing areas. They have home ranges, the home ranges of males being usually 2-8 square kilometers in size, and overlapping each other. Dominant males tolerate males passing through their territory except when they are in mating season, when dangerous fights break out. They are active at night and early morning. They spend the middle of the day wallowing in lakes, rivers, ponds, and puddles to cool down. They are extremely good swimmers. Over 10 distinct vocalizations have been recorded.

Indian rhinos have few natural enemies, except for tigers. Tigers sometimes kill unguarded calves, but adult rhinos are less vulnerable due to their size. Humans are the only other animal threat, hunting the rhinoceros primarily for sport or for the use of its horn. Mynahs and egrets both eat invertebrates from the rhino's skin and around its feet. Tabanus flies, a type of horse-fly are known to bite rhinos. The rhinos are also vulnerable to diseases spread by parasites such as leeches, ticks, and nematodes. Anthrax and the blood-disease septicemia are known to occur.[2]

[edit] Diet

The Indian Rhinoceros is a grazer. Their diet consists almost entirely of grasses, but the rhino is also known to eat leaves, branches of shrubs and trees, fruits and submerged and floating aquatic plants.[2]

Feeding occurs during the morning and evening. The rhino uses its prehensile lip to grasp grass stems, bend the stem down, bite off the top, and then eat the grass. With very tall grasses or saplings, the rhino will often walk over the plant, with its legs on both sides, using the weight of its body to bush the end of the plant to the level of the mouth. Mothers also use this technique to make food edible for their calves. They drink for a minute or two at a time, often imbibing water filled with rhinoceros urine.[2]

[edit] Social life

The Indian Rhinoceros forms a variety of social groupings. Adult males are generally solitary, except for mating and fighting. Adult females are largely solitary when they are without calves. Mothers will stay close to their calves for up to four years after their birth, sometimes allowing an older calf to continue to accompany her once a newborn calf arrives. Subadult males and females form consistent groupings as well. Groups of two or three young males will often form on the edge of the home ranges of dominant males, presumably for protection in numbers. Young females are slightly less social than the males. Indian Rhinos also form short-term groupings, particularly at forest wallows during the monsoon season and in grasslands during March and April. Groups of up to 10 rhinos may gather in wallows—typically a dominant male with females and calves, but no subadult males.[9]

Indian Rhinoceros
Indian Rhinoceros

The Indian Rhinoceros makes a wide variety of vocalizations. At least ten distinct vocalizations have been identified: snorting, honking, bleating, roaring, squeak-panting, moo-grunting, shrieking, groaning, rumbling and humphing. In addition to noises, the rhino uses olfactory communication. Adult males urinate backwards, as far as 3–4 meters behind them, often in response to being disturbed by observers. Like all rhinos, the Indian Rhinoceros often defecates near other large dung piles. The Indian Rhino has pedal scent glands which are used to mark their presence at these rhino latrines. Males have been observed walking with their heads to the ground as if sniffing, presumably following the scent of females.[9]

In aggregations, Indian Rhinos are often friendly. They will often greet each other by waving or bobbing their heads, mounting flanks, nuzzling noses, or licking. Rhinos will playfully spar, run around, and play with twigs in their mouth. Adult males are the primary instigators in fights. Fights between dominant males are the most common cause of rhino mortality, and males are also very aggressive toward females during courtship. Males will chase females over long distances and even attack them face-to-face.[9] Unlike African Rhinos, the Indian Rhino fights with its incisors, rather than its horns.[10]

[edit] Reproduction

Indian Rhino at San Diego Zoo, California, USA.
Indian Rhino at San Diego Zoo, California, USA.

In zoos, females may breed as young as four, but in the wild females are usually six before breeding begins.[11] The higher age in the wild may reflect that females need to be large enough to avoid being killed by the aggressive males. The Indian Rhinoceros has a very lengthy gestation period of around 15.7 months. The interval between births ranges from 34–51 months.[12] In captivity, males may breed at five years. But in the wild, dominant males do the breeding, and rhinos do not not attain dominance until they are older and larger. In one five-year field study, only one rhino who achieved mating success was estimated to be younger than 15.[13]

[edit] Range

The rhino once inhabited areas from Pakistan to Burma & Bangladesh and may have even roamed in China. But because of human influence their range has shrunk and now they only exist in small populations in northeastern India and Nepal.

Elephant safari after Rhinoceros unicornis in Chitwan National Park
Elephant safari after Rhinoceros unicornis in Chitwan National Park

On the former abundance of the species, Thomas C. Jerdon wrote in 1874 in the Mammals of India:

This huge rhinoceros is found in the Terai at the foot of the Himalayas, from Bhotan to Nepal. It is more common in the eastern portion of the Terai than the west, and is most abundant in Assam and the Bhotan Dooars. I have heard from sportsmen of its occurrence as far west as Rohilcund, but it is certainly rare there now, and indeed along the greater part of the Nepal Terai;... Jelpigoree, a small military station near the Teesta River, was a favourite locality whence to hunt the Rhinoceros and it was from that station Captain Fortescue, of the late 73rd N.I., got his skulls, which were, strange to say, the first that Mr. Blyth had seen of this species, of which there were no specimens in the Museum of the Asiatic Society at the time when he wrote his Memoir on this group.

—Jerdon, T. C. 1874 The mammals of India.

[edit] Population & Threats

In the nineteenth and end early twentieth century, the Indian Rhinoceros was hunted relentlessly. Reports from the middle of the nineteenth century claim that some military officers in Assam individually shot more than 200 rhinos. In the early 1900s, colonial officials became concerned at the rhino's plummeting numbers. By 1908 in Kaziranga, one of the rhino's main ranges, the population had fallen to around 12 individuals. In 1910, all rhino hunting in India became prohibited.[2]

This rhino is a major success of conservation. Only 100 remained in the early 1900s and now their population has increased but even so they are still endangered.

The Indian rhino is illegally poached for its horn, which some cultures in East Asia believe has healing and potency powers and therefore is used for Traditional Chinese Medicine and other Oriental medicines. Habitat loss is another threat. Fewer than 2500 individuals remain in the wild, and the species is endangered.

The Indian and Nepalese governments have taken major steps toward Indian Rhinoceros conservation with the help of the World Wildlife Fund (WWF). The Kaziranga National Park and Manas National Park in Assam, Pobitora reserve forest in Assam (having the highest Indian rhino density in the world), Orang National park of Assam, Laokhowa reserve forest of Assam having a very small population and Royal Chitwan National Park in Nepal are homes for this endangered animal.

Demographic trends of Rhinoceros unicornis. Sources : here.

YEAR TOTAL INDIA NEPAL
1910 100
1952 350 300 50
1958 700 400 300
1963 600
1964 625 440 185
1966 740 575 165
1968 680
1971 630
1983 1000
1984 1500
1986 1711 1334 377
1987 1700
1990 1700
1994 1900
1995 2135 1600 535
1997 2095
1998 2100
2000 2500
2002 2500
2005 2400

[edit] In captivity

Indian Rhinos have been somewhat tamed and trained in circuses, but remain dangerous and unpredictable animals. The Indian Rhinoceros was initially difficult to breed in captivity. The first recorded captive birth of a rhinoceros was in Kathmandu in 1826, but another successful birth would not occur for nearly 100 years; in 1925 a rhino was born in Calcutta. No rhinoceros was successfully bred in Europe until 1956, but in the second half of the 20th century, zoos became adept at breeding Indian rhinoceros. By 1983, nearly 40 had been born in captivity.[2]

[edit] Cultural depictions

The Rhinoceros
Albrecht Dürer, 1515
woodcut, 24.8 × 31.7 cm
See also: Dürer's Rhinoceros

The Indian Rhinoceros was the first rhino widely known outside its range. The first rhinoceros to reach Europe in modern times arrived in Lisbon on May 20, 1515. King Manuel I of Portugal planned to send the rhinoceros to Pope Leo X, but the rhino perished in a shipwreck. Before dying, however, the rhino had been sketched by an unknown artist. A German artist named Albrecht Dürer, saw the sketches and descriptions and created a woodcut of the rhino, known ever after as Dürer's Rhinoceros. Though the drawing had some anatomical inaccuracies (notably the hornlet protruding from the rhino's shoulder), his sketch became the enduring image of a rhinoceros in western culture for centuries.

[edit] Footnotes

  1. ^ Asian Rhino Specialist Group (1996). Rhinoceros unicornis. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 11 May 2006. Listed as Endangered (EN B1+2cde v2.3)
  2. ^ a b c d e f g h i j Laurie, W.A.; E.m. Lang, and C.P. Groves (1983). "Rhinoceros unicornis". Mammalian Species (211): 1–6. doi:10.2307/3504002. 
  3. ^ a b Xu, Xiufeng; Axel Janke, and Ulfur Arnason. "The Complete Mitochondrial DNA Sequence of the Greater Indian Rhinoceros, Rhinoceros unicornis, and the Phylogenetic Relationship Among Carnivora, Perissodactyla, and Artiodactyla (+ Cetacea)". Molecular Biology and Evolution 13 (9): 1167–1173. 
  4. ^ a b Lacombat, Frédéric. The evolution of the rhinoceros.  In Fulconis 2005, pp. 46–49.
  5. ^ Tougard, C.; T. Delefosse, C. Hoenni, and C. Montgelard (2001). "Phylogenetic relationships of the five extant rhinoceros species (Rhinocerotidae, Perissodactyla) based on mitochondrial cytochrome b and 12s rRNA genes". Molecular Phylogenetics and Evolution 19 (1): 34–44. doi:10.1006/mpev.2000.0903. 
  6. ^ Cerdeño, Esperanza (1995). "Cladistic Analysis of the Family Rhinocerotidae (Perissodactyla)". Novitates. American Museum of Natural History. ISSN 0003-0082. 
  7. ^ Dinerstein 2003, pp. 10–15
  8. ^ Dinerstein 2003, pp. 272
  9. ^ a b c Dinerstein 2003, pp. 283–286
  10. ^ Dinerstein 2003, pp. 134–135
  11. ^ Dinerstein 2003, pp. 142
  12. ^ Dinerstein 2003, pp. 142
  13. ^ Dinerstein 2003, pp. 148–149

[edit] References

[edit] External links

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