Introduction

Nilgiri tahr ( Nilgiritragus hylocrius,Ogilby, 1838) 

Formerly   Hemitragus hylocrius. Generic name was changed to  Nilgiritragus to be  in tune with the latest phylogenic research by Ropiquet and Hassanin.(Ropiquet and Hassanin, 2005 Molecular Phylogenetics and Evolution,Volume 36,Number 1, Pages 154-168  

The Nilgiri tahr was first named Kemas hylocrius by Ogilby (1838). In 1845 Gray re-christened the Nilgiri tahr as Capra warryato. This was subsequently changed to Kemas warryato in 1852 (Lydekker, 1913). Warryato is an English rendition of the Tamil term for the Nilgiri tahr. In 1859 Blyth included the Nilgiri tahr in the genus Hemitragus, naming it H. hylocrius (Lydekker, 1913).The current view is that there are three species of tahr, the Himalayan tahr (Hemitragus jemlahicus), the Nilgiri tahr (Nilgiritragus hylocrius), and the Arabian tahr- (Arabitragus jayakari). There is some variation in the spelling of the English name for this genus; it appears both as "tahr" and "thar". Both are an Anglicized form of the Nepali term for serow (Capricornis sumatraensis; Green, 1978). "tahr" is now the accepted spelling for the Himalayan species,  Nilgiri species and the Arabian species. However, English speaking South Indians also use the term "ibex" or "Nilgiri ibex". The Tamil name for Nilgiri tahr is "varai ad" or "varai adoo" which translates to "cliff goat". The comparable Malayalam term is "mala adu" (Prater, 1965). Interestingly, Ogilby (1838) based the original name for Nilgiri tahr, (Kemas hylocrius) on the understanding that it's local name was "jungle sheep" (jungle or wood corresponding to the root "hyla" and the Greek "krios" which means ram). However, in the English speaking community in the High Range, "jungle sheep" refers to the barking deer (Muntiacus muntjak), whereas "ibex" is the longstanding name for Nilgiri tahr (Jerdon, 1874; Fletcher, 1911). Gray's (1842) "warryato" is a much more appropriate name, but Ogilby's (1838) remains as the standard one by rules of precedence( Rice 1984).  

 Nilgiri tahr is an endangered mountain ungulate listed in  schedule I of the Indian Wildlife (Protection) Act 1972 and considered as endangered by the IUCN.  The species was assessed as endangered using the 1994 Red List Categories and Criteria as EN B1+2acd, C2a on 6/30/2000 (Assessors:CAMP Workshop, India). In the 2008 Redlist also the species was assessed as endangered.( Assessors:Alembath, M. & Rice, C.G, Evaluators Harris, R. & Festa-Bianchet, M. (Caprinae Red List Authority) ). It is the congener of the Himalayan tahr Hemitragus jemlahicus, found from Kashmir to Bhutan (Schaller, 1971) and the Arabian tahr Arabitragus jayakari, which is confined to the mountain district of Oman and adjoining rocky slopes of Hajar  mountains in United Arab Emirates

Synonyms

Kemas hylocrius (Ogilby, 1837)

Capra warrayato (Gray, 1842)

Kemas warrayato (Gray,1852)

Hemitragus hylocrius (Ogilby, 1838)

Common Names

Nilgiri Tahr

Varayadu (Malayalam)

Varaiaadu (Tamil)

Tahr des monts Nilgiri ( French) Rice, 1990

Nilgiritahr(German) Rice, 1990

Intiantari ( Finnish)

Range size:

Area of occupancy- (pre-colonial) 4000-5000km2

Extent of occurrence-(present) 400-500km2

 

Elevation:

Upper limit - 2695mt (Anaimudi)

Lower limit (present)- 600mt.

                   (past)    - 300mt.

 

Population Estimations


1000 (Schaller,1970)

2200 (Davidar,1978)

2234 (Rice,1984)

2500 (Shackleton.1997)

1950 (Daniels et al., 2006).  

2600- Min (Easa et al., 2010).

 

Reported Measurements of Nilgiri Tahr
 
Source of Information  Adult Weight Height At Shoulder  Length of Tail
Lydekker,1913   99-107 cm  

Prater,1971

 

  100-110 cm  

Wilson,1980

 

101.8 kg (M)
53.4 kg (F)
   
Alembath,1982 100kg(M)

60kg(F)

110cm(M)

75cm(F)

10-15cm

Rice,1990

 

100 kg (M)
50 kg (F)
110 cm (M)
80 cm (F)
10-15 cm

Nowak,1991

50-100 kg 61-106 cm 9-12 cm

Robinson,2005

 

80-100kg (M)
50 kg (F)
   
         

  Food plants of the Nilgiri Tahr (Rice, 1984)

Species

Family

Habit

Ranunculus reniformis

Ranunculaceae

Herb

Polygala sibrica

Polygalaceae

Herb

Hypericum mysorense

Hypericaceae

Shrub

Eurya japonica

Ternstroemiaceae

Shrub/Tree

Impatiens tomentosa

Balsaminaceae

Herb

Crotalaria fysonii

Fabaceae

Herb

Crotalaria scabrella

Fabaceae

Herb

Oldenlandia swertioides

Rubiaceae

Herb

Anaphalis bournei

Compositae

Herb

Anaphalis lawii

Compositae

Herb

Eupatorium adenophorum

Compositae

Herb

Lactuca hastate

Compositae

Herb

Wahlenbergia gracilis

Campanulaceae

Herb

Lobelia sp

Campanulaceae

Herb

Vaccinum leschenaultia

Vaccinaceae

Herb

Gaultheria fragrantissima

Ericaceae

Shrub

Pedicularis perrottetii

Scrophulariaceae

Herb

Sopubia trifida

Scrophulariaceae

Herb

Strobilanthes kunthianus

Acanthaceae

Shrub

Polygonum chinense

Polygonaceae

Herb

Elaeagnus kologa

Elaeagnaceae

Herb

Curculigo orchioides

Amaryllidaceae

Herb

Cyanotis sp

Commelinaceae

Herb

Eriocaulon brownianum

Eriocaulaceae

Herb

Carex lindleyana

Cyperaceae

Sedge

Sehima nervosum

Poaceae

Grass

Chrysopogon zeylanicus

Poaceae

Grass

Tripogon bromoides

Poaceae

Grass

Tripogon ananthaswamianus

Poaceae

Grass

Ischaemum indicum

Poaceae

Grass

Arundinella mesophylla

Poaceae

Grass

Arundinella fuscata

Poaceae

grass

Agrostis peninsularis

Poaceae

Grass

Andropogon polyptychus

Poaceae

Grass

Andropogon lividus

Poaceae

Grass

Themeda quadrivalvis

Poaceae

Grass

Themeda triandra

Poaceae

Grass

Isachne bourneorum

Poaceae

Grass

 

The Nilgiri tahr has short grey-brown or dark coat. There are facial markings, particularly distinct in mature males, consisting of a dark brown muzzle separated from a dark cheek by a white stripe running down from the base of horns. Females and immature males are an overall yellowish-brown to grey, with the underparts being paler (Lydekker, 1913; Prater, 1971; Rice, 1988; Nowak, 1991). Adult males weigh atound 100Kg and stands at 110 Cm at shoulder height. Adult females weigh at 50 Kg and stands at 80 Cms at shoulder height (Rice, 1990). Females have two nipples, unlike the two other species of tahr which have four (Nowak, 1991).  Both sexes of N. hylocrius bear relatively short curving horns. An estimated 2000 of the species exist in the wild.  Older males a are called Saddlebacks as they have a distinctive silvery saddle-patch marks on the rump.  The horns of females are shorter and slenderer.The main breeding season (rut) of wild Nilgiri tahr is from June to August during the monsoons (Rice, 1990; Robinson, 2005). Conception is for a period of 6 months. Peak in births occutr in January and February. New born tahr is called a Kid. By two months of age the kid follows its mother (Wilson, 1980) but they are not weaned until four to six months (Wilson, 1980; Rice, 1990). Sexual maturity occurs around 16 months (Wilson, 1980; Rice, 1990).Average life expectancy for Nilgiri tahr in the wild is estimated to be only three or 3.5 years, although the potential life span is at least 9 years (Rice, 1988; Rice, 1990). Annual mortality at Eravikulam NP was estimated to be 44–52% for young, 31–37% for yearlings, and 17–24% for adults. Life expectancy at birth was estimated at 3–3·5 years. There was evidence for mortality incurred by predation, disease, accidents, and injury during intraspecific combat, and thermal stress.((Rice, 1988)

The Nilgiri Tahr (Nilgiritragus hylocrius) is the only species of Caprine ungulate that is found south of the Himalayas in India. The eleven other species of Indian Caprine ungulates are confined to the Himalayan biogeographical zones. The Nilgiri Tahr presently occurs patchily over a short 400km stretch of the southern Western Ghats that spans the high altitude plateau of the Nilgiris and the hills of the Kanyakumari district; the total area of which is a mere 5% of the entire Western Ghats region.

The reason for the rather local distribution of the Tahr is its preference for a habitat that is predominantly of grasslands adequately sheltered by steep rocky cliffs; a unique habitat type that has rightly given the species the local name Varai Aadu (= Cliff Goat). These grasslands receive not less than 1500mm of rainfall annually and enjoy a short dry season and as such are restricted to just 7 high altitude landscapes (1200-2600m ASL) in the southern Western Ghats.

Having been exterminated from the northernmost Tahr landscape, the high altitude grasslands of southwestern Karnataka during the past 50 years, the Tahr is at present found only within 6 high altitude landscapes. And within these 6 landscapes, 18 localities have sustained small to large populations that vary in size between 20 and 550 animals. Estimates made at various times during the past 30 years placed the population size of the Nilgiri Tahr between 2000 and 2500 over its entire range.

It is evident that the Nilgiri Tahr had reached the brink of extinction sometime during the latter half of the 19th century. Early interventions by the erstwhile Nilgiri Game Association and High Range Game Association and modern conservation initiatives guided by the Indian Wildlife (Protection) Act of 1972 have aided a rather dramatic comeback of the species in less than 150 years.