The nilgai (Boselaphus tragocamelus), sometimes called nilgau, is an antelope, and is one of the most commonly seen wild animals of central and northern India and eastern Pakistan; it is also present in parts of southern Nepal. The mature males appear ox-like and are also known as blue bulls. The nilgai is the biggest Asian antelope. Nilgai stand 4–5 feet at the shoulder and are 6-6.6 feet long. Their tails are 15 to 18 inches. Mature nilgai typically weigh 260 to 525 pounds. Nilgai have thin legs and a robust body that slopes down from the shoulder. Their long, narrow heads are topped by two small conical horns which are straight and tilted slightly forward. Horns on trophy males are normally 8.5- 10 inches. They have an erectile mane on the back of the neck and a tubular shaped "hair pennant" on the midsection of the throat.
Female nilgai have a short yellow-brown coat. Males' coats gradually darken to a grey-blue as they reach maturity. They have white spots on the cheeks and white coloring on the edges of the lips. They also have a white throat bib and a narrow white stripe along the underside of the body that widens at the rear. Nilgai can be found in single sex or mixed sex herds of 4-20, although old bulls are sometimes solitary.