Rhinoceros unicornisIndian rhinoceros

Geographic Range

Found in northern Pakistan, India, Nepal, Bangladesh, and Assam.

Habitat

Alluvial plain is the primary and preferred habitat. Adjacent swamp and forest areas are also used.

Physical Description

Both male and female R. unicornis have a single dark horn on the nose measuring up to 529 mm, which is made from agglutinated hairs. Their skin has many loose folds, especially distinct around the neck region in males, which give the appearance of a suit of armor. The skin is covered with large tubercules.

  • Range mass
    1500 to 2000 kg
    3303.96 to 4405.29 lb

Reproduction

Breeding occurs throughout the year. Only dominant bulls mate, and it is believed that they can assess the reproductive status of females through scent. Courtship may seem aggressive--males chase females and fighting often ensues. After a gestation period of 480 days, one young is born weighing 70 kg. Weaning usually occurs in one year, although it may last up to 18 months. Females have young at intervals of about three years. One week before the next birth, the female will chase away her previous calf. Sexual maturity is reached at an age of 9 years for males, and 4 for females. The lifespan is about 40 years.

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • Average number of offspring
    1
    AnAge
  • Average gestation period
    479 days
    AnAge
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    1678 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    2557 days
    AnAge

Lifespan/Longevity

Behavior

Rhinoceros unicornis is usually solitary except for females with young. Loosely bound aggregations of a few individuals do occur, especially at wallowing grounds or foraging areas. There are loosely defined territories in males which are not well defended, and often these territories overlap. Occasionally rhino interactions are aggressive, characterized by charges, and horn clashes. Fighting between males is often a cause of death when population densities are high. Approximately 10 vocalizations are known for rhinos, including snorts, roars, and honks. Scent deposition is common, and often large communal dung heaps are formed.

Communication and Perception

Food Habits

The diet consists of grass, fruit, leaves, branches, aquatic plants, and cultivated crops. Tall reedy grasses are preferred to short species. The prehensile upper lip is used to curl around grass stems to bring them into the mouth. When eating aquatic plants, rhinos submerge their entire heads and tear the plant up by the roots. Foraging occurs at night, in early morning, or late afternoon to avoid the heat of the day. Rhinoceros unicornis drinks daily and is fond of mineral licks.

Economic Importance for Humans: Positive

Asian rhino horn can be sold for more than twice its weight in gold. After processing, it has been known to reach $30,000 per kg. The horn is used as a medicine and an aphrodisiac. Medicinal purposes are as a pain reliever and a fever suppressant. There are no scientific studies, however, that show that rhino horn is effective for any of these purposes. In addition to the horn, rhino hide, blood, urine, and dung also have economic value.

  • Positive Impacts
  • body parts are source of valuable material

Economic Importance for Humans: Negative

Rhinos have been known to injure crops by trampling and consumption. At one point, a government bounty was established to keep rhinos from ruining tea plantations. In addition, there are recorded fatalities as a result of an attacks by rhinos, usually when a mother with calf was startled.

  • Negative Impacts
  • injures humans
  • crop pest

Conservation Status

Total wild populations number 1700. Rhinoceros unicornis is severely threated by hunting activities due to the huge economic value of the horn. This species is listed endangered by the IUCN and USDI and is on Appendix 1 of CITES. Current projects are underway to reintroduced populations in areas where they have been extirpated. Such projects will only be successful if the reason for the initial downfall of rhinos --overhunting by humans--can be eliminated. Efforts to control poaching and illegal wildlife trade will help in the recovery of the Indian rhino. One population in Nepal is protected with 700 armed troops and rangers, almost 2 guards per rhino. Aside from overhunting, the loss of alluvial plain habitat to agriculture has resulted in a reduction of suitable rhino habitat.

Other Comments

Rhinos often wallow and bathe in the heat of the day. This is important both for thermoregulation and for avoiding flies.

Contributors

Bridget Fahey (author), University of Michigan-Ann Arbor.

Glossary

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

scrub forest

scrub forests develop in areas that experience dry seasons.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

References

Nowak, R.M. Walker's Mammals of the World, 5th Edition. Johns Hopkins University Press.

Grizemek's Encyclopedia of Mammals. McGraw-Hill Publishing Co.