The nilgai is the largest antelope in Asia. It stands 1–1.5 metres (3.3–4.9 ft) at the shoulder; the head-and-body length is typically between 1.7–2.1 metres (5.6–6.9 ft). Males weigh 109–288 kilograms (240–635 lb); the maximum weight recorded is 308 kilograms (679 lb). Females are lighter, weighing 100–213 kilograms (220–470 lb). Sexual dimorphism is prominent; the males are larger than females and differ in colouration.
A sturdy thin-legged antelope, the nilgai is characterised by a sloping back, a deep neck with a white patch on the throat, a short mane of hair behind and along the back ending behind the shoulder, and around two white spots each on its face, ears, cheeks, lips and chin. The ears, tipped with black, are 15–18 centimetres (5.9–7.1 in) long. A column of coarse hair, known as the "pendant" and around 13 centimetres (5.1 in) long in males, can be observed along the dewlap ridge below the white throat patch. The tufted tail, up to 54 centimetres (21 in), has a few white spots and is tipped with black. The forelegs are generally longer, and the legs are often marked with white "socks".
While females and juveniles are orange to tawny, males are much darker – their coat is typically bluish grey. The ventral parts, the insides of the thighs and the tail are all white. A white stripe extends from the underbelly and broadens as it approaches the rump, forming a patch lined with dark hair. Almost white, though not albino, individuals have been observed in the Sariska National Park (Rajasthan, India) while individuals with white patches have been recorded at zoos. The hairs, typically 23–28 centimetres (9.1–11.0 in) long, are fragile and brittle. Males have thicker skin on their head and neck that protect them in fights. The coat is not well-insulated with fat during winter, and consequently severe cold might be fatal for the nilgai.
Only males possess horns, though a few females may be horned as well. The horns are 15–24 centimetres (5.9–9.4 in) long but generally shorter than 30 centimetres (12 in). Smooth and straight, these may point backward or forward. The horns of the nilgai and the four-horned antelope lack the ringed structure typical of those of other bovids.
*information courtesy of https://en.wikipedia.org/wiki/Nilgai