The Nilgiri Tahr (Nilgiritragus Hylocrius) known locally as the Nilgiri ibex or simply ibex, is an ungulate that endemic to the Nilgiri Hills and the species is found in a roughly 400 km stretch in southern portion of the Western Ghats in the states of Tamil Nadu and Kerala in southern India. It is the state animal of Tamil Nadu. Despite its local name, it is more closely related to the sheep of the Ovis genus than the ibex and wild goats of the Capra genus. The local distribution of the species is attributed to the animal’s preference for the habitat with grasslands with steep rocky cliff shelters. The Eravikulam National Park has an estimated 700-800 Nilgiri Tahr, the highest density and largest wild population in the world. Nilgiri tahr commences feeding at the break of day and feed until late evening. They feed and rest intermittently, the rest intervals becoming longer as the day advances, until they become active again towards the evening. The tahr was observed to feed primarily on 19 species of grasses, 12 species of shrubs along with a lichen and fresh shoots of dwarf bamboo.
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. A grown-up male is known as ‘saddle back’. The overall colouring is deep chocolate brown. This is particularly dark, almost black on the front of the fore and hind legs, the shoulder, the side of the abdomen, side of the face and the front of the muzzle. These contrast sharply with white facial stripe which drops from the forehead towards the corners of the mouth just anterior to the eyes, the white carpal patches on the front and outside of the forelegs and the silvery saddle. The side of the neck where it meets the shoulder is also sometimes lightened, as is the flank posterior to the saddle and an area around the eye The male would be bigger and darker than the female and has a silver saddle like patch on its back.Adult males weigh around 100 kg and stands at 110 cm at shoulder height. Long black hairs from a mane and mid dorsal stripe. The horns curve uniformly back and have no twist.
Female Nilgiri Tahr is shorter and slighter than their male counterparts. In contrast to the striking pelage of the male, the female is almost uniformly grey. The carpal patch is black against the light background. The facial markings are present but only faintly and the area around the eye and the cheek below it are brown. The horns of females are shorter and slenderer. Adult females weigh at 50 kg and stands at 80 cm at shoulder height. Females hv two nipples, unlike the two other species of tahr which have four. The main breeding season of wild Nilgiri Tahr is from June to August during the monsoons. Conception is for a period of 6 months. Mating takes place during the monsoon season and calving is during January – February. The female gestates for about 180 days and usually gives birth to one kid per pregnancy. New born tahr is called a Kid. By two months of age the kid follow its mother but they are not weaned until four to six months. Sexual maturity is achieved at around three years of age. The average life expectancy for Nilgiri tahr in the wild is estimated to be only 3 or 3.5 years although the potential life span is at least 9 years.