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Boselaphus tragocamelusnilgai

By Melody Benton

Ge­o­graphic Range

Bose­la­phus trago­camelus, also called the nil­gai an­te­lope, evolved in pen­nin­su­lar India dur­ing the Ter­tiary ge­o­log­i­cal pe­riod, where they are also cur­rently found. They were im­ported to the United States as zoo an­i­mals be­fore the mid-1920s and re­leased into Texas about 1930. Today they are found on large ranches in Kenedy and Willacy coun­ties of Texas.

Habi­tat

Nil­gai an­telopes live in dry areas with a va­ri­ety of land types. They range from grassy, steppe wood­lands, to hill­sides. In India, they occur in the foothills of the Hi­malayan Moun­tains south­ward to Mysore. The brush coun­try of South Texas is well suited to their nat­ural pref­er­ences.

Phys­i­cal De­scrip­tion

Nil­gai an­te­lope are among the largest of the asian an­telopes. They stand about 120-150cm at the shoul­der and have a body length of 180-200cm. They have a short coat which is yel­low-brown in fe­males and turns blue-grey in adult males. Calves are pale brown. The hair of the adult nil­gai an­te­lope is thin and oily, but the skin is thick on the chest and neck of the males. There are patches of white on the face and below the chin. This ex­tends into a broad, white "bib" on the throat. In males below the "bib" hangs a tuft of hair, or "beard" that can be as long as 13cm.

A white band along the brisket area goes over the ab­domen and spreads be­tween the hind legs, which forms a nar­row rump patch that is out­lined with darker hair. They have slen­der legs which sup­port their stocky bod­ies. The head is long and slen­der and males have horns about 20-25cm, which are black in color, sharp, and curved.

  • Range mass
    120 to 240 kg
    264.32 to 528.63 lb

Re­pro­duc­tion

Fe­males and males re­main seg­re­gated for most of the year, ex­cept for when the bulls join the cows for breed­ing. Breed­ing groups con­sist of one dom­i­nant bull and one to many cows. Mat­ing usu­ally oc­curs from De­cem­ber to March, but breed­ing can occur through the year. The ges­ta­tion pe­riod is 240-258 days and it is com­mon for nil­gai an­telopes to bear twins. Fe­males can con­ceive at 18 months of age, but very few mate be­fore 3 years of age. Males are sex­u­ally ma­ture by 2 1/2 years of age, but can­not com­pete very well with other males until 4 years of age.

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • Range number of offspring
    1 to 2
  • Average number of offspring
    1.3
  • Average number of offspring
    1.5
    AnAge
  • Range gestation period
    8.27 to 8.6 months
  • Average gestation period
    8.435 months
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    815 days
    AnAge
  • Parental Investment
  • altricial
  • post-independence association with parents

Lifes­pan/Longevity

Be­hav­ior

Nil­gai an­telopes are usu­ally found in herds of about 10 an­i­mals, but larger groups of 20 to 70 have been seen. They are din­ural with most ac­tiv­ity in the early morn­ing and late af­ter­noon. They have good eye­sight and hear­ing that is equal to or bet­ter than the white-tail deer, but they do not have a good sense of smell. Though they are nor­mally silent, they can make a roar­ing like vo­cal­iza­tion when alarmed. When chased they can reach speeds up to 29 mph.

Com­mu­ni­ca­tion and Per­cep­tion

Food Habits

Nil­gai an­telopes graze and browse, with grass as the main source of their diet. In Asia, they eat mainly woody plants. In Texas, they eat mesquite, oak, par­tridge peas, cro­ton, night­shade, and a va­ri­ety of grasses. Some­time they up­grade their diet by eat­ing plant parts, such as flow­ers, seeds, fruits, leaves, and stem tops.

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

The nil­gai an­te­lope is hunted for its meat. Over­hunt­ing may neg­a­tively im­pact pop­u­la­tions of nil­gai an­te­lope.

  • Positive Impacts
  • food

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Nil­gai an­te­lope may dam­age human food crops in the areas in which they are found.

Con­ser­va­tion Sta­tus

Hunt­ing by hu­mans threat­ens nil­gai an­telopes.

Other Com­ments

The nil­gai an­te­lope was first de­scribed by Pal­las in 1766. Nil­gai is from the Hindi word nil­gaw which means "blue bull" re­fer­ring to the color of the adult male. The species name, Bose­la­phus trago­camelus is de­rived from 'bos', Latin for ox, 'elaphos', Greek for deer, 'tra­gos', Greek for a male goat, and 'kame­los', Greek for camel.

Con­trib­u­tors

Melody Ben­ton (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, Phil Myers (ed­i­tor), Mu­seum of Zo­ol­ogy, Uni­ver­sity of Michi­gan-Ann Arbor.

Glossary

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

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.

food

A substance that provides both nutrients and energy to a living thing.

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

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

sexual

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

social

associates with others of its species; forms social groups.

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

1990. Grz­imek's En­cy­clo­pe­dia of Mam­mals. New York, New York: Mc­Graw Hill.

1994. "The Mam­mals of Texas-On­line Edi­tion (Nil­gai)" (On-line). Ac­cessed No­vem­ber 17, 1999 at http://​www.​nsrl.​ttu.​edu/​tmot/​bosetrag.​htm.

Huff­man, B. "Nil­gai (Bose­la­phus trago­camelus)" (On-line). Ac­cessed No­vem­ber 17, 1999 at http://​www.​pathcom.​com/​~dhuff­man/nilgai.​html.

Nowak, R. 1991. Walker's Mam­mals of the World (Fifth Edi­tion). Bal­ti­more, Mary­land: John Hop­kins Uni­ver­sity Press.

Sheffield, W. 1997. "The Hand­book of Texas On­line (Nil­gai An­te­lope)" (On-line). Ac­cessed No­vem­ber 17, 1999 at http://​www.​tsha.​utexas.​edu/​handbook/​online/​articles/​view/​NN/​tcn1.​html.

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