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Hemitragus hylocriusNilgiri tahr

By Adam Herman

Geographic Range

Nilgiri tahrs (Hemitragus hylocrius) were once abundant in grass-woodland mosaic habitat in rugged hills and mountain slopes of the southern Indian states of Kerala and Tamil Nadu. The endangered Nilgiri tahrs are endemic to the Western Ghats Mountains in south India. They are now limited to some 17 populations in the Nilgiri, Anamalai, Palani and Highwavy Hills, the Eravikulam area of the High Range, and possibly a few other mountains in the Western Ghats. (Mishra and Johnsingh, 1998; Rice, 1988)

Habitat

They prefer grass-woodland mosaic habitat in rugged hills, mountain slopes and plateaus at altitudes ranging from 1,200-2,200 m. Nilgiri tahr frequent the fringes of the grass-covered plateaus dominated by two main types of grass, Eulalia phaeotrix and Andropogon polyptichus. (Davidar, 1978; Rice, 1986; Rice, 1988)

  • Range elevation
    1200 to 2200 m
    3937.01 to 7217.85 ft

Physical Description

Nilgiri tahrs are goat-like animals with a short coat and short, laterally flattened and curved horns. Males are black with a silver saddle and bristly mane, while females are grayish brown with white bellies also having latterly-flattened curved horns. Measurements of these animals are as follows: head and body length 90-140 cm; height at the shoulder 61-106 cm; tail length 9-12 cm; weight 50-100 kg. (Rice, 1988; Nowak, 1991)

  • Sexual Dimorphism
  • male larger
  • sexes colored or patterned differently
  • ornamentation
  • Range mass
    50 to 100 kg
    110.13 to 220.26 lb
  • Range length
    90 to 140 cm
    35.43 to 55.12 in

Reproduction

Nilgiri tahrs are polygynous, males compete for access to females through battles. Males will mate with as many females as they can gain access to. (Nowak, 1991)

Mating takes place throughout the year, but there is a birth peak in winter. Wild Nilgiri tahrs rarely give birth to twins. A single offspring is born after a gestation period of 180-242 days, and females can give birth twice in one year. Reproductive output varies greatly from year to year. Nilgiri tahrs breed well in captivity. (Rice, 1988; "Status accounts for selected threatened Indian mammals", 2001)

  • Breeding interval
    Breeding occurs twice yearly.
  • Breeding season
    Mating occurs throughout the year but may peak in winter.
  • Range number of offspring
    1 to 2
  • Average number of offspring
    1
  • Average number of offspring
    1.3
    AnAge
  • Range gestation period
    6 to 8.07 months
  • Average gestation period
    7.03 months
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    669 days
    AnAge

Females nurse and care for their offspring until they reach independence.

Lifespan/Longevity

Nilgiri tahrs have a relatively short life expectancy. Life expectancy at birth is estimated to be 3-3.5 years, though they may live longer. (Rice, 1988)

  • Typical lifespan
    Status: wild
    3.0-3.5 (high) years

Behavior

Nilgiri tahrs are active intermittently from dawn to dusk and are primarily grazers, living in herds ranging from 6 – 104 animals, with average group sizes of 9 for all-female groups and 27 for mixed herds. Males battle on mountain slopes in competition for mates. (Rice, 1988; Davidar, 1978; Schaller, 1977)

Communication and Perception

The primary modes of communication are visual, auditory and olfactory. Pheromones released in their urine communicate information about mate identification and reproductive activity, spacing mechanisms, and alarm. (Nowak, 1991)

Food Habits

Preferred foods include various grasses and forbs. Species included among these various forage types are Eulalia phaeothrix, Andropogon polyptichus, Chrysopogon zelan, Eupatorium adenophoru, Strobilanthes kunthianus and Cymbopogon spp. (Rice, 1988)

  • Plant Foods
  • leaves

Predation

Anti-predator adaptions in Nilgiri tahrs include group defense and using horns for defense. Native predators of the Nilgiri tahr are the tiger (Panthera tigris), Indian wolves (Canis lupus) and dholes (Cuon alpinus). Another major predator are humans who poach these animals by means of shooting and snaring. (Mishra and Johnsingh, 1998; "Status accounts for selected threatened Indian mammals", 2001)

Ecosystem Roles

Nilgiri tahrs serve as a food source for predators such as tigers, wolves, and dholes. Their grazing maintains grass levels, which suppresses the probability of fire in grassland communities. (Schaller, 1977)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

Nilgiri tahrs are a valuable source of protein and income for local people. Unfortunately, poaching is the primary means of harvesting this animal. Therefore, this may be a positive economic importance for the local people but the continued poaching may eventually lead to the demise of the species. (Rice, 1988)

  • Positive Impacts
  • food
  • body parts are source of valuable material
  • ecotourism

Economic Importance for Humans: Negative

These animals may compete for grazing with domestic livestock. ("Status accounts for selected threatened Indian mammals", 2001)

Conservation Status

Nilgiri tahrs have been protected by government law in India since 1972. These animals are likely candidates for reintroduction and also breed well in captivity. They are not only threatened by poaching, they are threatened by grazing, competition with domestic stock, hydroelectric projects, and habitat loss to agriculture and eucalyptus and wattle plantations. Ecological studies are needed to form a basis of management plans since sustainable harvesting and/or licensed sport hunting of a restored population could be a valuable source of protein and income for local people in a safe and legal mannerr. ("Status accounts for selected threatened Indian mammals", 2001)

In 1986 total numbers were estimated at 2,000 – 2,200, relatively unchanged since 1978. Available evidence suggests that the three largest populations have remained approximately stable in recent years. The largest known populations consist of nearly 550 animals each existing in the Eravikulam and Nilgiri Hills National Parks. These two populations comprise approximately 50% of the remaining animals. The remaining populations are of less than 100 animals. (Rice, 1988; Rice, 1986; Davidar, 1978)

Contributors

Adam Herman (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor), University of Wisconsin-Stevens Point.

Glossary

acoustic

uses sound to communicate

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

crepuscular

active at dawn and dusk

diurnal
  1. active during the day, 2. lasting for one day.
dominance hierarchies

ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates

ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

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.

female parental care

parental care is carried out by females

folivore

an animal that mainly eats leaves.

food

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

herbivore

An animal that eats mainly plants or parts of plants.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

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.

nomadic

generally wanders from place to place, usually within a well-defined range.

oriental

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

World Map

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

polygynous

having more than one female as a mate at one time

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

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

sexual ornamentation

one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

References

World Conservation Monitoring Center. 2001. "Status accounts for selected threatened Indian mammals" (On-line ). Accessed 30 October 2002 at http://www.wcmc.org.uk/igcmc/rl_anml/indmams.html.

Davidar, E. 1978. Distribution and status of the Nilgiri tahr (*Hemitragus hylocrius*). Bombay Nat. Hist. Soc., 75: 815-844.

Mishra, C., A. Johnsingh. 1998. Population and conservation status of the Nilgiri tahr *Hemitragus hylocrius* in Anamalai Hills, South India. Biological Conservation, 86: 199-206.

Nowak, R. 1991. Walker's Mammals of the World, 5th edn. Baltimore and London: University Press.

Rice, C. 1986. Conservation of Tahr. Caprinae News, 1: 7-9.

Rice, C. 1988. Habitat, Population Dynamics, and Conservation of the Nilgiri tahr, *Hemitragus hylocrius*. Biological Conservation, 44: 137-156.

Schaller, G. 1977. Mountain Monarchs. Chicago, USA: Univ. of Chicago Press.

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