The nilgai (Boselaphus tragocamelus) (/ˈnilˌɡaɪ/, literally meaning "blue cow") is the largest antelope of Asia, and is ubiquitous across the northern Indian subcontinent.

Sexual dimorphism is prominent – while females and juveniles are orange to tawny, adult males have a bluish-grey coat.

Herbivores, nilgai prefer grasses and herbs, though they commonly eat woody plants in the dry tropical forests of India.

The nilgai prefers areas with short bushes and scattered trees in scrub forests and grassy plains.

Nilgai have been considered a pest in several north Indian states, as they ravage crop fields and cause considerable damage.

The vernacular name "nilgai" /ˈnɪlˌɡaɪ/ comes from the fusion of the Hindi words nil ("blue") and gai ("cow").

[2] 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").

[11] The generic name Boselaphus comes from the combination of the Latin bos ("cow" or "ox") and the Greek elaphos ("deer").

[2] A 1992 phylogenetic study of mitochondrial DNA sequences showed a strong possibility of a clade consisting of Boselaphini, Bovini, and Tragelaphini.

Bovini consists of the genera Bubalus, Bos, Pseudoryx (saola), Syncerus (African Buffalo), Bison and the extinct Pelorovis.

[22] Fossils of Protragoceros and Sivoreas dating back to the late Miocene have been discovered not only in Asia and southern Europe but also in the Ngorora Formation (Kenya) and are thought to belong to the Boselaphini.

[24] Alan W. Gentry of the Natural History Museum reported the presence of another boselaphine, Mesembriportax, from Langebaanweg (South Africa).

[27][28] 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.

[2] A column of coarse hair, known as the "pendant" and around 13 cm (5.1 in) long in males, can be observed along the dewlap ridge below the white throat patch.

[30] A white stripe extends from the underbelly and broadens as it approaches the rump, forming a patch lined with dark hair.

[40][41] Significant numbers occur in the Terai lowlands in the foothills of the Himalayas; the antelope is abundant across northern India.

It is difficult to account for the animals being thus so widely divided from their usual haunts unless as has been generally supposed, these Southern specimens are the progeny of a semi-domesticated herd, which, at some by-gone period, had escaped from the preserve of a native potentate.The nilgai is diurnal (active mainly during the day).

A 1991 study investigated the daily routine of the antelope and found feeding peaks at dawn, in the morning, in the afternoon and during the evening.

The defecation process is elaborate-the antelope stands with his legs about a metre apart, with the rump lowered and the tail held almost vertical; it stays in the same posture for at least ten seconds after relieving itself.

[43] In India, the nilgai shares its habitat with the four-horned antelope, chinkara, chital and blackbuck; its association with the gaur and the water buffalo is less common.

[2][60] In Sariska Reserve, it prefers herbs and grasses; grasses become more important in the rainy season, while during winter and summer it feeds additionally on Butea monosperma flowers, foliage of Anogeissus pendula, Capparis sepiaria, Grewia flavescens and Zizyphus mauritiana), pods of Acacia nilotica, A. catechu and A. leucophloea, and fruits of Zizyphus mauritiana.

Woody plants eaten include Acacia nilotica, A. senegal, A. leucophloea, Clerodendrum phlomidis, Crotalaria burhia, Indigofera oblongifolia, Morus alba and Zizyphus nummularia; herbs favoured are Cocculus hirsutus, Euphorbia hirta and Sida rhombifolia.

These fights are characterised by displays of the enlarged chest, the throat patch and the beard while holding the head upright; and threatening the opponent by running with the horns pointed toward him and circling him.

The male, stiff and composed, approaches the receptive female, who keeps her head low to the ground and may slowly walk forward.

[52] Births peak from June to October in the Bharatpur National Park, and from April to August in southern Texas.

The gods saw him and said: "Prajapati is doing a deed that is not done".Nilgai are extensively featured in paintings, dagger hilts and texts from the Mughal era (16th to 19th centuries);[74][75] their representation, however, is less frequent than that of horses and camels.

[86] Farmers in Neemuch (Madhya Pradesh) went on a hunger strike in 2015 demanding compensation for the damage caused by nilgai.

[93] Shivanshu K. Srivastava, a columnist and social activist, wrote that "The culling of nilgais (blue bulls) in Bihar in July 2016 was so deplorable that it doesn't need any justification.

The excuse given for this slew by the State government, the then environment minister Prakash Javadekar and the judiciary is so illogical that it mocks all the solutions available to stop the nilgais from destroying the farms.

In summer, the faeces of the antelope contained nearly 1.6 percent nitrogen, that could enhance the quality of the soil up to a depth of 30 cm (12 in).