Rhinoceros unicornis, Photo: Michael Lahanas
Rhinoceros unicornis Linnaeus 1758
* Rhinoceros unicornis on Mammal Species of the World.
The Indian Rhinoceros (Rhinoceros unicornis) is also called Greater One-horned Rhinoceros and Asian One-horned Rhinoceros and belongs to the Rhinocerotidae family. Listed as a vulnerable species, the large mammal is primarily found in parts of north-eastern India and in protected areas in the Terai of Nepal, where populations are confined to the riverine grasslands in the foothills of the Himalayas. Weighing between 2260 kg to 3000 kg, it is the fourth largest land animal and has a single horn, which measures 20 to 57 cm (7.9 to 22 in) in length.
The Indian rhinoceros once ranged throughout the entire stretch of the Indo-Gangetic Plain but excessive hunting reduced their natural habitat drastically. Today, about 3,000 rhinos live in the wild, 2,000 of which are found in India's Assam alone.
In size, one-horned rhinos are equal to the African white rhinos; together they are the largest of all rhino species. Fully grown males are larger than females, weighing from 2,200 to 3,000 kg (4,900 to 6,600 lb). Female one-horned rhinos weigh about 1,600 kg (3,500 lb). They are from 1.7 to 2 m (5 ft 7 in to 6 ft 7 in) tall and can be up to 4 m (13 ft) long. The record-sized specimen weighed approximately 3,500 kg (7,700 lb).
The Rhino's single horn is present in both males and females, but not on newborn young. The black 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 cm (9.8 in), but has been recorded up to 57.2 cm (22.5 in) in length. The nasal horn curves backwards from the nose. In captive animals, the horn is frequently worn down to a thick knob.
This 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.
In captivity, four are known to have lived over 40 years, the oldest living to be 47.
Distribution and habitat
One-horned rhinos once ranged across the entire northern part of the Indian subcontinent, along the Indus, Ganges and Brahmaputra River basins, from Pakistan to the Indian-Burmese border, including parts of Nepal, Bangladesh and Bhutan. They may have also existed in Myanmar, southern China and Indochina.They prefer the alluvial plain grasslands of the Terai and Brahmaputra basin. As a result of habitat destruction and climatic changes their range has gradually been reduced so that by the 19th century, they only survived in the Terai grasslands of southern Nepal, northern Uttar Pradesh, northern Bihar, northern Bengal, and in the Brahmaputra Valley of Assam.
On the former abundance of the species, Thomas C. Jerdon wrote in 1867:
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.
Today, their range has further shrunk to a few pockets in southern Nepal, northern Bengal and the Brahmaputra Valley. In the 1980s, rhinos were frequently seen in the narrow plain area of Royal Manas National Park in Bhutan. Today, they are restricted to habitats surrounded by human-dominated landscapes, so that they often occur in adjacent cultivated areas, pastures, and secondary forests.
Rhinos are regionally extinct in Pakistan.
In 2007, the total population was estimated to be 2,575 individuals, of which 2,200 lived in Indian protected areas:
in Kaziranga National Park: 1,855 — increased from 366 in 1966
Pobitora Wildlife Sanctuary shelters the highest density of Indian rhinos in the world — with 84 individuals in 2009 in an area of 38.80 km2 (14.98 sq mi).
In Nepal, a total of 378 individuals were estimated to live by 2007, most of them in Chitwan National Park, 35 individuals in Bardia National Park, and six individuals in Sukla Phanta Wildlife Reserve. In March 2008, a rhino count conducted in the Terai recorded 408 individuals in and around Chitwan National Park, and 22 individuals in the Karnali flood plain area of Bardia National Park. There are 5 rhinos in the Sukla Phanta Wildlife Reserve.
In Pakistan's Lal Suhanra National Park, two rhinos from Nepal were introduced.
Ecology and behavior
Rhinos 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 to 8 km2 (0.77 to 3.1 sq mi) large 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 very good swimmers. Over 10 distinct vocalizations have been recorded.
Indian rhinos have few natural enemies, except for tigers who sometimes kill unguarded calves, but adult rhinos are less vulnerable due to their size. 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.
They can run at speeds of up to 55 km/h (34 mph) for short periods of time and are excellent swimmers. They have excellent senses of hearing and smell but relatively poor eyesight.
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.
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 push the end of the plant down 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.
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.
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.
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. Unlike African Rhinos, the Indian Rhino fights with its incisors, rather than its horns.
In zoos, females may breed as young as four, but in the wild females are usually six before breeding begins. 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. In captivity, males may breed at five years. But in the wild, dominant males do the breeding and rhinos do 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. The Cincinnati Zoo was the first zoo to breed an Indian Rhino using AI, since it is risky to use AI on rhinos, the baby died 12 hours after it was born.
Sport hunting became common in the late 1800s and early 1900s. Indian rhinos were hunted relentlessly and persistently. Reports from the middle of the 19th century claim that some military officers in Assam individually shot more than 200 rhinos. By 1908, the population in Kaziranga had decreased to around 12 individuals. In the early 1900s, the species had declined to near extinction.
Poaching for rhinoceros horn became the single most important reason for the decline of the Indian rhino after conservation measures were put in place from the beginning of the 20th century, when legal hunting ended. From 1980 to 1993, 692 rhinos were poached in India. In India's Laokhowa Wildlife Sanctuary 41 rhinos were killed in 1983, virtually the entire population of the sanctuary. By the mid-1990s, poaching had rendered the species extinct there.
In 1950, Chitwan’s forest and grasslands extended over more than 2,600 km2 (1,000 sq mi) and were home to about 800 rhinos. When poor farmers from the mid-hills moved to the Chitwan Valley in search of arable land, the area was subsequently opened for settlement, and poaching of wildlife became rampant. The Chitwan population has repeatedly been jeopardized by poaching: in 2002 alone, poachers have killed 37 animals cruelly in order to saw off and sell their valuable horns.
There are six recorded ways of killing rhinos:
Shooting is by far the most common method used; rhino horn traders hire sharpshooters and often supply them with rifles and ammunition.
Poaching, mainly for the use of the horn in Traditional Chinese Medicine has remained a constant and has led to decreases in several important populations. Apart from this, there have been serious declines in quality of habitat in some areas, due to
severe invasion by alien plants into grasslands affecting some populations;
The species is inherently at risk because over 70% of its population occurs at a single site, Kaziranga National Park. Any catastrophic event such as disease, civil disorder, poaching, habitat loss would have a devastating impact on the Indian rhino's status. On the other hand, small population of rhinos may be prone to in-breeding depression.
The species has been included on CITES Appendix I since 1975. The Indian and Nepalese governments have taken major steps towards Indian Rhinoceros conservation, especially with the help of the World Wide Fund for Nature (WWF) and other non-governmental organizations. In the early 1980s, a rhino translocation scheme was initiated. The first pair of rhinos was reintroduced from Nepal's Terai to Pakistan's Lal Suhanra National Park in Punjab in 1982.
In 1910, all rhino hunting in India became prohibited. In 1984, five rhinos were relocated to Dudhwa National Park — four from the fields outside the Pabitora Wildlife Sanctuary and one from Goalpara.
In 1957, the country's first conservation law inured to the protection of rhinos and their habitat. In 1959, Edward Pritchard Gee undertook a survey of the Chitwan Valley, recommended creation of a protected area north of the Rapti River and of a wildlife sanctuary south of the river for a trial period of ten years. After his subsequent survey of Chitwan in 1963, he recommended extension of the sanctuary to the south. By the end of the 1960s, only 95 rhinos remained in the Chitwan Valley. The dramatic decline of the rhino population and the extent of poaching prompted the government to institute the Gaida Gasti – a rhino reconnaissance patrol of 130 armed men and a network of guard posts all over Chitwan. To prevent the extinction of rhinos the Chitwan National Park was gazetted in December 1970, with borders delineated the following year and established in 1973, initially encompassing an area of 544 km2 (210 sq mi). Since 1973, the population has recovered well and increased to 544 animals around the turn of the century. To ensure the survival of rhinos in case of epidemics animals are translocated annually from Chitwan to the Bardia National Park and the Sukla Phanta Wildlife Reserve since 1986.
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 did not occur for nearly 100 years; in 1925 a rhino was born in Kolkata. No rhinoceros was successfully bred in Europe until 1956. On September 14, 1956 Rudra was born in Zoo Basel, Switzerland.
In the second half of the 20th century, zoos became adept at breeding Indian rhinoceros. By 1983, nearly 40 had been born in captivity. As of 2010, 32 Indian rhinos were born at Zoo Basel, which means that most animals kept in a zoo are somehow related to the population in Basel, Switzerland.
Due to the success of Zoo Basel's breeding program, it holds the international studbook since 1972 and coordinates since 1990 the European Endangered Species Programme (EEP), which ensures that the captive global Indian rhinoceros population of about 174 rhinos (2010) stays as genetically healthy as possible.
The modern scientific designation Rhinoceros unicornis is adopted from the Greek: ρινό- ("rhino-" — a certain nasal condition) and -κερος ("-keros" — horn of an animal) and Latin: "uni-" meaning single and "-cornis" meaning horn. This 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.
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. 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.
Fossils of Rhinoceros unicornis appear in the Middle Pleistocene. In the Pleistocene, the Rhinoceros genus ranged throughout South and Southeast 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.
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. 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. The Sumatran Rhino may have diverged from the other Asian rhinos as long as 15 million years ago.
The British public had their first chance to view a rhinoceros ( presumably this species) in 1683; it unknowingly caused a political row when the notorious Judge Jeffreys, in one of his lighter moments, spread a rumour that his chief rival, Lord Guildford, had been seen riding on it.
Assam state of India has one-horned rhino as the official state animal. It is also the organizational logo for Assam Oil Company Ltd.
^ Grubb, Peter (16 November 2005). "Order Perissodactyla (pp. 629-636)". In Wilson, Don E., and Reeder, DeeAnn M., eds. Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press, 2 vols. (2142 pp.). p. 636. ISBN 978-0-8018-8221-0. OCLC 62265494.
Martin, E. B. (2010). From the jungle to Kathmandu : horn and tusk trade. Kathmandu: : Wildlife Watch Group. ISBN 9789994682096.
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