Nilgai, also known as Blue Bull, is one of the most commonly found wild animals of northern India as well as eastern Pakistan. Even though it is an antelope, it looks quite similar in appearance to an ox. Therefore, it has been given the name of Blue bull of India. The average lifespan of the Neelgai is 21 years. Physical Traits Indian Blue bull antelope stands tall, at a height of 1.2 to 1.5 m (4 to 5 feet). It grows to length of somewhere between 1.8 and 2 m and weighs around 120 to 240 kg. The tail of a Neelgai is 40 to 45 cm in length. The largest male blue bull antelope was seen in the state of Texas and it weighed over 272 kg. A baby Neelgai weighs between 13.6 and 15.9 kg. The strong body of the Blue bull of India is balanced on comparatively thin legs. It has two small conical horns on the top of a long and narrow head. The horns are straight and at the same time, slightly forward tilted. Horns of male Nilgai are 21.6 to 25.4 cm in length. On the backside of the neck is an erectable mane, while the throat is adorned with a tubular-shaped “hair pennant”. Female Neelgai is yellowish-brown in color and is shorter in height as compared to her male counterpart. As a male Nilgai attains maturity, its coat starts turning grayish-blue in color. There are white spots on the cheeks and white coloring on the edges of the lips. Behavior

Nilgai antelope is a sociable creature, usually found in single-sex or mixed-sex herds. The membership of a herd may be anywhere between four and twenty. In winter, male blue bulls of northern India are known to form herds of 30 to 100 animals. Male Blue bulls, after they reach old age, may be found leading a solitary life. One can also come across individual male or female nilgais in cultivated or semi-urban areas. Natural Habitat Nilgai is a diurnal creature, found inhabiting Indian grasslands and woodlands. It avoids dense forest and has preference for plains and low hills with shrubs. Blue bulls are found in the northern plains of India, stretching on from the base of the Himalayas in the north, to the state of Karnataka in the South. Their range also covers the area from the Gir forest, all along the entire eastern length of Pakistan, across the border of Rajasthan in the West to the states of Assam and West Bengal in the East. Mating Behavior Nilgai attains maturity at the age of 18 months. The gestation period lasts for 8 months, after which, usually, twins are born.

In some cases, the number of young ones may be one or three also. Diet Blue bulls of India are herbivorous creatures, surviving primarily on grasses, leaves, buds, and fruits. Predators of Nilgai The main predators of the blue bulls include tigers and lions. Leopards may attack calves, but are not capable of killing an adult Nilgai. Status Nilgai antelope has been listed in the ‘Low Risk’ category by the IUCN. The estimated population of Nilgai in India is approximately 100,000. The main threat to the Neelgai is from the destruction of its habitat to accommodate the ever-swelling human population.
Nilgai (Boselaphus tragocamelus), also called bluebuck, the largest Asian antelope . The nilgai is indigenous to the Indian subcontinent, and Hindus accord it the same sacred status as cattle (both belong to the subfamily Bovinae). Accordingly, the nilgai is the only one of the four Indian antelopes that is still abundant.

Nilgai is the Hindustani word for “blue cow,” which describes the blue-gray of adult bulls. (Cows are orange-brown.) The nilgai’s conformation, however, is more horselike than cowlike: it has a long neck with a short upright mane, a bony narrow head, a barrel-like chest, strong legs, and high withers sloping back to the croup. On the other hand, it has a hock-length cow’s tail that ends in a black tuft. Both sexes have similar markings; white areas include the cheek spots, ear tips, large throat bib, brisket, belly, rump patch, and underside of the tail. Its lower legs are banded black and white. Maximum contrast is achieved in prime males, which turn nearly black. They grow much bigger than cows, up to 1.5 metres (5 feet) tall and 300 kg (660 pounds), compared with 214 kg (471 pounds) for cows; they also have a thicker neck and a tassel of black hair bordering the white bib. But the male’s cowlike horns are quite small, being 15–18 cm (6–7 inches) long.

Nilgais inhabit flat and rolling dry savanna covered by thin woodland and scrub. Requiring minimal cover, they avoid dense woods and are most abundant in central and northwest India. (However, Texas has over 36,000 descendants of nilgais that were introduced in the 1930s, most of which are feral.) Mixed feeders, they prefer grass but also browse acacias and other trees and like flowers and fruits. They will stand on their hind legs to browse as high as possible. Overgrazing by cattle often leaves little food for the nilgais, which compensate by raiding crops. They are active during the day and even in the hottest weather seek shade only for midday siestas. Extending the usual morning and late-afternoon feeding peaks, nilgais often begin eating before dawn and keep feeding after dark. They drink regularly during the hot season but can go two to three days without water in cool weather.

The nilgai is only moderately gregarious. Herds of 10 or fewer are usual, and groups of 20 or more are exceptional. The sexes remain separate most of the time, and only one mature bull in either a bachelor or female herd is the rule. Herd membership is fluid, and the only lasting association is between mothers and calves. Adult males are often seen alone and wander widely. Whether the mating system is based on male territoriality or a male rank hierarchy remains unclear. Presence of dung middens suggests territorial demarcation, but these are used by all nilgais, even calves. There is a mating peak in November and December, but calves are born in almost every month, after a gestation of more than eight months. Cows breed again soon after calving and may be followed by calves of different ages. Over half of nilgai births are of single calves, but triplets are not uncommon. Calves spend a month in hiding before beginning to accompany their mothers.