The nilgai is the largest antelope of Asia, and is ubiquitous across the northern Indian subcontinent. It is the sole member of the genus Boselaphus, which was first described by Peter Simon Pallas in 1766. The nilgai stands 1–1.5 m (3.3–4.9 ft) at the shoulder; males weigh 109–288 kg (240–635 lb), and the lighter females 100–213 kg (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, 15–24 cm (5.9–9.4 in) long.

The tribe Tragelaphini, or the spiral-horned antelopes, are bovines that are endemic to sub-Saharan Africa. These include the bushbucks, kudus, and the elands. The scientific name is in reference to the mythical creature the tragelaph, a Chimera with the body of a stag and the head of a goat. They are medium-to-large, tall, long-legged antelopes characterized by their iconic twisted horns and striking pelage coloration patterns.