Animal Info - Indian Rhinoceros

(Other Names: Gainda, Great Indian One-horned, Great Indian, or Greater One-horned, or Greater One-horned Asian Rhinoceros; Panzernashorn, Rhinocéros Unicorne de l'Inde; Rinoceronte Unicornio Índico)

Rhinoceros unicornis

Status: 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, Early Development, Dispersal, Maximum Age, Diet, Behavior (Senses, Activity Patterns, Wallowing, Movement), Social Organization, Age and Gender Distribution, Mortality and Survival, Density and Range)
5. References


Profile

Pictures: Indian Rhino #1 (Huffman 2004); Indian Rhino #2 (30 Kb JPEG) (Intl. Rhino Found. 2002) 

The Indian rhinoceros has one horn (both male and female), and its skin has loose folds and rivet-like knobs which make it appear armored. A female Indian rhino weighs about 1600 kg (3500 lb), while a male weighs about 2200 kg (4800 lb). The average height of a female is 1.6 m (5.2'); males average 1.8 m (5.9') tall. The Indian rhino is found throughout its present range in alluvial plain habitats: riverine grasslands with grass up to 8 m (26') tall and marshy areas bordered by riverine woodlands, drier sal forest, or tropical almond forest. It now often uses cultivated areas, pastures, and modified woodlands. The Indian rhino's diet consists mainly of grass but also includes fruit, leaves, branches of trees and shrubs, and cultivated crops.   

The Indian rhino is active mostly at night, in early morning and in the late afternoon. The middle of the day is usually spent resting, either in the shade or in wallows. Apart from cow-calf pairs, Indian rhinos rarely form groups. Adult males are usually solitary, but they sometimes occur in temporary associations at wallows and grazing grounds where they often feed or rest together but move independently of each other. The Indian rhino is not territorial. The home ranges of dominant bulls overlap with one another, with ranges of weaker males that do not attempt to mate, and with ranges of females. 

In historic times, the Indian rhino occurred in the sub-Himalayan region all along the Indus, Ganges and Brahmaputra River basins. It disappeared over much of its range between 1600 - 1900. By the beginning of the 20th century, it was close to extinction. At that point there was a change in human treatment of the Indian rhino: hunting was halted and general legal protection was established. For most of the 20th century, populations of the Indian rhino have been concentrated in southern Nepal and northeastern India. By the late 20th century, the Indian rhino was confined to a few isolated patches in the Nepal terai, West Bengal (India), and the Brahmaputra Valley in Assam (India). Fortunately, the total population increased considerably during the second half of the 20th century (See Population Estimates below.).

The main reason for the decline of the Indian rhino from its historical levels was the loss of alluvial plain grasslands to agricultural development, which destroyed the rhino's prime habitat, led to conflicts with human interests, and made the rhino more accessible to hunters. In the early 20th century, hunting was prohibited. Currently, with most Indian rhinos occurring only in sanctuaries, poaching (mainly for use of its horn in Oriental medicine) is still a major problem, as well as competition for grazing with domestic stock and trespass in sanctuaries by villagers for firewood and fodder.


Tidbits

*** As early as 1952, the public of Assam, India (where many of the remaining Indian rhinos occurred) was becoming sensitive to the value of the region's wildlife and the importance of its preservation (Gee 1952). This was especially significant for the continued survival of the Indian rhino, because experience showed that, in some areas, the rhino preferred the vicinity of villages and cultivation to undisturbed forests and grassland. This was apparently due to its preference for man-grown crops. The rhinos did not object to sharing their grazing with domestic stock. In Nepal the common grazing grounds were apparently grazed by domestic stock by day and rhinos by night (Gee 1959).

*** India and Nepal increased security against poaching beginning in 1994, and poaching has decreased significantly. About 40 rhino poachers were in jail in Nepal in 1995, and the sentences are usually upheld. Most poachers in India and Nepal are caught through informers, who are paid for information on a regular basis by the International Trust for Nature Conservation. The funds are raised from individual donors and through a collection box at Tiger Tops Jungle Lodge in Chitwan National Park, Nepal (Martin & Vigne 1996).

***As an indication of the incentive for poaching of rhino horns, consider that the wholesale value of Asian rhino horn increased from US $35/kg ($16/lb) in 1972 to $18,000/kg ($8000/lb) in 1991. The retail price, after the horn has been shaved or powdered for sale, has at times and in some East Asian markets exceeded $50,000/kg ($23,000/lb). By contrast, in November 1996 pure gold was worth about $12,000/kg ($5500/lb) (about one quarter of the maximum value of rhino horn). (Nowak 1999) 

*** In Kaziranga National Park in Assam, India, tiger predation is the second biggest threat to the Indian rhino after poaching. (Oryx 1998b)

*** The rhino's horn is composed of agglutinated fibers sitting on the skull. It is not firmly connected to the bones of the skull.


Status and Trends

IUCN Status:

[The IUCN (International Union for the Conservation of Nature; also called the World Conservation Union) is the world’s largest conservation organization. Its members include countries, government agencies, and non-governmental organizations.  The IUCN determines the worldwide status of threatened animals and publishes the status in its Red List.]

Countries Where the Indian Rhinoceros Is Currently Found:

2004: Occurs in Bhutan, India and Nepal. (IUCN 2004)

Population Estimates:

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

History of Distribution:

The Indian rhino occurred in the sub-Himalayan region in historic times, all along the Indus, Ganges and Brahmaputra River basins. The western limit of its range was the foothills of the Hindu Kush west of Peshawar (Pakistan). The eastern limit of its historic range is uncertain. Some authors believe that it occurred in Cambodia, Laos, Thailand and Vietnam. Others believe that it never occurred east of the India-Myanmar border, and that reports from east of that border were mistaken, caused by confusing the Indian rhino with the Javan rhino (Rhinoceros sondaicus) or the Sumatran rhino (Dicerorhinus sumatrensis).

The Indian rhino remained common in northwest India and Pakistan until about 1600. It disappeared from those regions shortly thereafter and declined sharply in the remainder of its range over the next 300 years. The main reason for this was the loss of alluvial plain grasslands to agricultural development, which destroyed the rhino's prime habitat, led to conflicts with human interests, and made the rhino more accessible to hunters. Sport hunting of the species by both Europeans and Asians became very popular in the late 19th and early 20th centuries. Even more Indian rhinos were systematically slaughtered during this period for a government bounty established to protect tea plantations from damage due to rhinos. By the first decade of the 20th century, the Indian rhino was close to extinction. In India there were only a few scattered survivors, the main group comprised of 12 individuals along the Brahmaputra River in the Kaziranga area of Assam. In Nepal there were perhaps another 50. At that point there was a change in human treatment of the Indian rhino: the bounty and sport hunting were halted, general legal protection was established, and Kaziranga was made a reserve. (Nowak 1999) 

For most of the 20th century, populations of the Indian rhino have been concentrated in southern Nepal and northeastern India. By the late 20th century, the Indian rhino was confined to a few isolated patches in the Nepal terai, West Bengal (India), and the Brahmaputra Valley in Assam (India) (Javed 1993). Fortunately, the total population increased considerably during the second half of the 20th century (See Population Estimates above.).

Distribution Map (5 Kb GIF) (Huffman 2004)
Distribution Map (30 Kb JPEG) (Intl. Rhino Found. 2004)

Threats and Reasons for Decline:

By the early 1900's, the Indian rhino was already thought to be a "vanishing race." Hunting was important to the decline, but man's modification of the rhino's habitat for cultivation and grazing was instrumental in reducing the rhino population to the point where hunting became critical (IUCN 1967). Currently, with most Indian rhinos occurring only in sanctuaries, poaching (mainly for use of its horn in Oriental medicine) is still a major problem, as well as competition for grazing with domestic stock and trespass in sanctuaries by villagers for firewood and fodder.


Data on Biology and Ecology

Size and Weight:

A female Indian rhino weighs about 1600 kg (3500 lb); a male weighs about: 2200 kg (4800 lb). The average height of a female is 1.6 m (5.2'); for a male, it is 1.8 m (5.9') (Laurie et al. 1983).

Habitat:

In the past, the Indian rhino was recorded from a number of habitats, including marshy lowland and reed beds; tall grass or bush with patches of savanna and occasional streams and swamps; thick tree and scrub riverine forest; and dry, mixed forest. It is found throughout its present range in alluvial plain habitats: riverine grasslands with grass up to 8 m (26') tall and marshy areas bordered by riverine woodlands, drier sal forest, or tropical almond forest.  Furthermore, its range now has been so restricted by human activity that it often uses cultivated areas, pastures, and modified woodlands. (Laurie et al. 1983, Nowak 1999)

The Indian rhino is one of the species that live in both the Himalaya and Indo-Burma Biodiversity Hotspots (Cons. Intl.) and the Terai-Duar Savannas & Grasslands Global 200 Ecoregion. (Olson & Dinerstein 1998, Olson & Dinerstein 1999)

Age to Maturity:

A female Indian rhino is fully grown at 4 years in captivity but not until about 6.5 years in the wild.  A male Indian rhino is fully grown at 8 years of age in captivity but at about 10 years of age in the wild. In Chitwan (Nepal), female Indian rhinos have their first calves at 6 - 8 years of age. (Laurie et al. 1983)  The average age of females at sexual maturity is 7.0 - 7.5 years (Nowak 1999).

Gestation Period:

Average: 16 months (462 - 491 days) (n = 31) (Laurie et al. 1983).

Birth Season:

Mating takes place throughout the year (Laurie et al. 1983).

Birth Rate:

One Indian rhino calf is usually born at a time. The time between births can be as short as 22 months but usually is 2 - 4 years (Macdonald 1984).  In Nepal the birth interval is commonly 3 - 5 years (Nowak 1999).

In one study, three estimates of annual female reproductive rate were derived (using various data sources): 0.357 calves born/adult female/year (assuming a 2.8 year intercalving interval), 0.286 calves/adult female/year (assuming a 3.5 year intercalving interval), and, 0.25 calves born/adult female/year (assuming a 4 year intercalving interval). (Rothley et al. 2004) 

Early Development:

Calves are suckled frequently up to the age of 1 year and only rarely after the age of 18 months. Up to the age of 6 months, calves are left alone for periods as long as 90 minutes while their mothers feed up to 800 m (2600') away. (Laurie et al. 1983) 

Dispersal:

Male calves leave their mothers at an average age of 39 months compared with 34 months for female calves (Laurie et al. 1983). A calf is driven away by its mother at least one week before the birth of the next calf. (Nowak 1999) 

Maximum Age:

The record longevity in captivity is 47 years (Laurie et al. 1983).

Diet:

The Indian rhino's diet consists mainly of grass. It also includes fruit, leaves, branches of trees and shrubs, and cultivated crops.  Salt licks are visited regularly. (Nowak 1999) The Indian rhino uses its prehensile upper lip to browse tall grass and shrubs. It can fold the tip of its lip away when feeding on short grass. (Macdonald 1984) The Indian rhino drinks daily from streams, rivers, lakes, puddles, or wallows. Rhinos often drink very dirty water heavily contaminated with rhino urine. (Laurie et al. 1983)

In Nepal, Indian rhinos were observed to feed on 183 species of plants, with grasses making up between 70 - 89% of the diet depending on the season. Other foods included fruits, leaves and branches of shrubs and trees, sedges and ferns, submerged and floating aquatic plants, and cultivated crops. (Laurie et al. 1983)

Behavior:

Females choose secluded areas to give birth in (Laurie et al. 1983).

Senses: For all species of rhino, smell is the strongest sense, although their mobile, tubular ears provide good hearing. The eyes, however, are small, and rhinos have poor vision. (Burnie & Wilson 2001)

Activity Patterns: The Indian rhino is active mainly at night, in early morning and in the late afternoon. The middle of the day is mainly spent resting, either in the shade or in wallows. During the monsoon this pattern changes slightly - there are cool, wet days when rhinos feed at mid-day. Crop-raiding takes place exclusively at night - much later during moonlit nights than during moonless or cloudy nights. Less time is spent feeding during the monsoon (36%) than during the spring (65%) and winter (57%). There is often a rest period during the night, between midnight and 0300 h (3:00 am). (Laurie et al. 1983)

Wallowing: The Indian rhino wallows in lakes, rivers, and temporary pools. In Chitwan, Nepal, it wallowed most frequently between June and October (51% of observations) and least frequently between December and March (4% of observations). Heat regulation is probably a major function of wallowing, but escape from flies, especially in tall grasslands during the monsoon, may also be important. (Laurie et al. 1983) 

Movement: The Indian rhino is the most aquatic rhino, wading and swimming with ease (Burnie & Wilson 2001).

Social Organization:

Apart from cow-calf pairs, Indian rhinos rarely form groups. Adult males are usually solitary, but they sometimes occur in temporary associations of up to nine rhinos of various sex and age classes. These groups form at wallows and grazing grounds where the rhinos often feed or rest together but move independently of each other. In one study in Chitwan, Nepal, only 15% of the sightings of Indian rhinos were groups other than cow-calf pairs. Only seven groups consisted of more than three individuals and the most common type of group was comprised of two or three subadults, usually subadult males, which had recently left their mothers. The largest group recorded in Chitwan was of six subadults. (Laurie et al. 1983)

Among Indian rhinos, there is some degree of range exclusivity but no true territoriality. The home ranges of dominant bulls overlap with one another, with ranges of weaker males that do not attempt to mate, and with ranges of females. When two dominant Indian rhino males meet, they may fight using their tusk-like lower incisors. These conflicts can end in the death of one of the combatants. (Laurie et al. 1983, Nowak 1999, Burnie & Wilson 2001)

Age and Gender Distribution:

The age distribution of Indian rhinos in Chitwan, Nepal was reported in two studies as: 1) 27% calves, 21% subadults, 32% adult females, and 20% adult males (Laurie et al. 1983); and 2) 14% calves, 14% subadults, and 65% adults (1988 data) (Rothley et al. 2004).  [Note: In both cases, the life stages are defined as: calves: ages less than 4 years, subadults: ages 4 - 6 years, and adults: ages 7 years and older.]

Mortality and Survival:

Annual natural mortality rates for the Indian rhino have been reported as: 2.8% for calves, 2.2% for subadults and 2.9% for adults in Chitwan, Nepal. These rates include natural mortality causes such as tiger predation, separation of calves from their mothers, floods, quicksand, and fights with conspecifics, but they do not include poaching. (Rothley et al. 2004) [Note: The life stages are defined as: calves: ages less than 4 years, subadults: ages 4 - 6 years, and adults: ages 7 years and older.]

Density and Range:

Density

Various studies have reported the following population densities of the Indian rhino: more than 2.0 rhinos/sq km (5.2 rhinos/sq mi) in Kaziranga, Assam in India (Laurie et al. 1983); up to 4.85 rhinos/sq km (12.6 rhinos/sq mi) in favored high-diversity habitat in Chitwan, Nepal (Nowak 1999); and 1.7 - 3.2 rhinos/sq km (4.4 - 8.3 rhinos/sq mi) in grasslands and a maximum of 13.3 rhinos/sq km (34.6 rhinos/sq mi) in riverine forest in Chitwan, Nepal (Nowak 1999)

Range

Female Indian rhinos have home ranges covering 9 - 15 sq km (3.5 - 5.8 sq mi). Ranges of breeding males in Chitwan, Nepal varied from at least 2 - more than 8 sq km (0.8 - 3.1 sq mi). The range can be temporarily enlarged when food and water supplies are low.  Conversely, ranges are smallest in the regions of greatest vegetational diversity, (Laurie et al. 1983, Macdonald 1984).


References

Anon. 1994a, Arkive, AZA 1998a, Burton & Pearson 1987, Cons. Intl., Cumming et al. 1990, Curry-Lindahl 1972, Dinerstein & McCracken 1990, Fitter 1974, Focus 2000, Foose 1990, Foose & van Strien 1997, Gee 1952, Gee 1958, Gee 1959, Gee 1963, Gee 1964, Huffman 2004, 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, Javed 1993, La Monte & Welch 1934, Laurie et al. 1983, Macdonald 1984, Martin 1985, Martin 2001, Martin et al. 1987, Martin & Vigne 1996, Nowak 1999, Nowak & Paradiso 1983, Olson & Dinerstein 1998, Olson & Dinerstein 1999, Oryx 1964b, Oryx 1966c, Oryx 1968a, Oryx 1970a, Oryx 1981b, Oryx 1998b, Oryx 2001b, Rothley et al. 2004, Sale & Singh 1987, Schumacher 1967, Shebbeare 1953, Talbot 1960, Talukdar 1997, Talukdar 2002, Vigne & Martin 1991, WCMC/WWF 1997


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