|The Mammals of Texas -
Artiodactyla : Family Bovidae :
Boselaphus tragocamelus (Pallas)
Description. A large antelope with short,
smooth horns in males. Horns average only 18 cm in
length, with lengths of only 23-30 cm the maximum.
Females usually do not grow horns, but may occasionally.
Nilgai stand 119-150 cm at the
shoulder, with prominent withers giving them a backline
that slopes to the rump. In bulls, powerful shoulders and
a thick neck tend to accentuate this sloping profile.
Overall coloration is gray to brownish
gray in males; females and young are brown to orangish
brown. Patches of white on the face and below the chin,
extending into a broad, white "bib" on the
throat, break up the ground coloration. A narrow white
band along the brisket area broadens over the abdomen and
spreads between the hind legs to form a narrow rump patch
that is edged with darker hair. Below the white bib hangs
a tuft of hair, or "beard," which may be as
long as 13 cm in males.
Bulls weigh 109-288 kg, with the
maximum about 306 kg. Females weigh 109-213 kg.
Distribution in Texas. Nilgai
are native to India and Pakistan, where they are the
largest species of antelope. Nilgai were imported into
Texas as game animals and have readily reproduced and
established free-ranging populations. They are the most
abundant free-ranging exotic ungulate in Texas and have
done especially well in South Texas. The majority of
Texas nilgai are found in free-ranging populations on
several large ranches in Kenedy and Willacy counties.
Habits. Avoiding densely wooded
areas, nilgai inhabit relatively dry areas of flat to
rolling country with a moderate cover of thin forest or
scrub. The South Texas brush country is ideally suited to
Forage preference is based primarily on
availability. Nilgai both graze and browse, with grasses
constituting the bulk of the diet. In Texas, mesquite,
oak, partridge pea, croton, nightshade, and a variety of
grasses are eaten.
Nilgai typically herd in small groups
of about 10 animals although larger groups of 20-70 are
occasionally seen. Males and females remain segregated
for most of the year, with bulls joining the cow-calf
groups only for breeding. In Texas, most mating activity
occurs from December through March; however, breeding can
occur throughout the year. The period of gestation is
240-258 days and nilgai commonly bear twins. In favorable
conditions females only 18 months of age can conceive,
but few females mate before 3 years of age. Males become
sexually mature by 2½ years of age but usually cannot
compete successfully with other males until about 4 years
In South Texas the life expectancy of
nilgai is about 10 years, providing they survive the most
vulnerable period from birth to about 3 years of
age, when adult proportions are attained. In Texas,
coyotes are the primary predator of nilgai calves but are
not of sufficient size to take full grown animals. In
addition to people and coyotes, cold weather can cause
significant mortality among nilgai in South Texas. Nilgai
have a thin coat and store only a meager winter fat
reserve. Although rare in South Texas, prolonged periods
of cold temperatures will dramatically reduce nilgai
populations. During the severe winter of 1972-73, 1,400
of 3,300 nilgai were killed by the weather in South
Texas. This die-off was exacerbated by previous brush
clearing, which resulted in forage loss and increased
competition with livestock and other wildlife.
* nonnative species
Photo courtesy of Texas Parks and Wildlife.