Nilgai (Boselaphus tragocamelus) male, in a potato field, Jamtra, MP, India


The nilgai or blue bull (Boselaphus tragocamelus) is the largest Asian antelope and is endemic to the Indian subcontinent. The sole member of the genus Boselaphus, the species was described and given its binomial name by German zoologist Peter Simon Pallas in 1766. The nilgai stands 1–1.5 metres (3.3–4.9 ft) at the shoulder; males weigh 109–288 kilograms (240–635 lb), and the lighter females 100–213 kilograms (220–470 lb). 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 crest of hair along the neck terminating in a tuft, and white facial spots. A column of pendant coarse hair hangs from the dewlap ridge below the white patch. Sexual dimorphism is prominent – while females and juveniles are orange to tawny, adult males have a bluish-grey coat. Only males possess horns, which are 15–24 centimetres (5.9–9.4 in) in length.

This picture shows a male nilgai in a potato field at Jamtra, in the Indian state of Madhya Pradesh.

Etymology

The vernacular name "nilgai" /ˈnɪlˌɡaɪ/ comes from the fusion of the Hindi words nil ("blue") and gai ("cow"). The word was first recorded in use in 1882. Alternative origins could be from the Persian gaw ("cow"). The nilgai has been referred to by a variety of names: neelghae,  nilgau, nilgo, nylghau, and nylghai, constructions referring to other "blue" animals. They are also known as white-footed antelope. During Mughal emperor Aurangzeb's reign (1658–1707) of India, the nilgai was known by the name nilghor ("nil" for "blue" and "ghor" for "horse").