Boselaphus tragocamelus
nilgai

Boselaphus tragocamelus, also called the nilgai antelope, evolved in penninsular India during the Tertiary geological period, where they are also currently found. They were imported to the United States as zoo animals before the mid-1920s and released into Texas about 1930. Today they are found on large ranches in Kenedy and Willacy counties of Texas.

Nilgai antelopes live in dry areas with a variety of land types. They range from grassy, steppe woodlands, to hillsides. In India, they occur in the foothills of the Himalayan Mountains southward to Mysore. The brush country of South Texas is well suited to their natural preferences.

Nilgai antelope are among the largest of the asian antelopes. They stand about 120-150cm at the shoulder and have a body length of 180-200cm. They have a short coat which is yellow-brown in females and turns blue-grey in adult males. Calves are pale brown. The hair of the adult nilgai antelope is thin and oily, but the skin is thick on the chest and neck of the males. There are patches of white on the face and below the chin. This extends into a broad, white "bib" on the throat. In males below the "bib" hangs a tuft of hair, or "beard" that can be as long as 13cm.

A white band along the brisket area goes over the abdomen and spreads between the hind legs, which forms a narrow rump patch that is outlined with darker hair. They have slender legs which support their stocky bodies. The head is long and slender and males have horns about 20-25cm, which are black in color, sharp, and curved.

Females and males remain segregated for most of the year, except for when the bulls join the cows for breeding. Breeding groups consist of one dominant bull and one to many cows. Mating usually occurs from December to March, but breeding can occur through the year. The gestation period is 240-258 days and it is common for nilgai antelopes to bear twins. Females can conceive at 18 months of age, but very few mate before 3 years of age. Males are sexually mature by 2 1/2 years of age, but cannot compete very well with other males until 4 years of age.

Nilgai antelopes are usually found in herds of about 10 animals, but larger groups of 20 to 70 have been seen. They are dinural with most activity in the early morning and late afternoon. They have good eyesight and hearing that is equal to or better than the white-tail deer, but they do not have a good sense of smell. Though they are normally silent, they can make a roaring like vocalization when alarmed. When chased they can reach speeds up to 29 mph.

Nilgai antelopes graze and browse, with grass as the main source of their diet. In Asia, they eat mainly woody plants. In Texas, they eat mesquite, oak, partridge peas, croton, nightshade, and a variety of grasses. Sometime they upgrade their diet by eating plant parts, such as flowers, seeds, fruits, leaves, and stem tops.

The nilgai antelope is hunted for its meat. Overhunting may negatively impact populations of nilgai antelope.

Nilgai antelope may damage human food crops in the areas in which they are found.

Hunting by humans threatens nilgai antelopes.

The nilgai antelope was first described by Pallas in 1766. Nilgai is from the Hindi word nilgaw which means "blue bull" referring to the color of the adult male. The species name, Boselaphus tragocamelus is derived from 'bos', Latin for ox, 'elaphos', Greek for deer, 'tragos', Greek for a male goat, and 'kamelos', Greek for camel.