Why Do They Keep to a Small Slice of South Texas?
THE NILGAI ANTELOPE is one of the most sought after exotic species in Texas. According to the Texas Parks & Wildlife Department, nilgai are native to Pakistan and India and they are truly unique animals.
“The male nilgai stands between 48 to 60 inches high at the shoulder and weighs between 480 and 540 pounds,” officals say. “The male (often called a blue bull) averages about one-fifth larger and heavier than the female. The hair on the body is short and wiry. Although in both sexes the neck is ornamented with a mane, only bulls develop a tuft of hair on the throat.
“The upper parts of males are generally iron gray, but the lower surface of the tail, stripes inside the ears, rings on the fetlocks, and underparts are white. The head and limbs are tawny, and the throat tuft and the tip of the tail are black. The females are more lightly colored. On both sexes, the forelegs are longer than the hind ones, and the head is long and pointed. The horns are short and carried only by males.”
According to the Texas State Historical Association, nilgais were brought to the United States from India as zoo animals before the mid-1920s and were released in South Texas about 1930.
“The King Ranch pioneered the release of nilgais in Texas. Between about 1930 and 1941, the ranch acquired several nilgais from zoo stock and released them in Kennedy County. With limited hunting and predation, protection, and favorable habitat, the nilgais adapted well. Their primary range now includes the area from Baffin Bay south to near Harlingen,” they reported.
These nilgais are free-ranging. The species, in fact, is hard to keep in fences—not because they leap over them, but because they can destroy them.
I have always wondered why—if nilgais have been present for nearly 100 years in South Texas, and they are free-ranging—they have not migrated farther north.
According to the Texas State Historical Association it has to do with the cold.
“Approximately 15,000 nilgais are now on Texas rangelands,” they said. “Nilgais will probably not become widespread because they suffer in extreme cold, and even in temperate South Texas they may die during unusually cold winters when food is scarce.”
I have seen nilgais on high-fenced ranches in Central Texas but those animals get supplemental feed, and I have heard of them dying off in temperatures that have little impact on other exotics.
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Nilgai a Threat to Deer?
A STUDY ENTITLED “Food Habits of Nilgai Antelope in Texas” by William Sheffield sheds somes interesting light on how these huge antelope impact cattle and deer.
Rumen analyses of 79 nilgai and 40 deer, collected on various feeding sites, and bite studies on the same sites using two captive nilgai and a trained steer showed no significant difference forage classes taken between the two methods.
“Nilgai preferred to feed on large open areas interspersed with cover and ponded water. They were grazers, their average diet consisting of 60 percent grasses, 25 percent forbs, and 15 percent browse. They augumented the nutritive level of their basic diet by selecting nutritious plant parts and changing their selections as the parts appeared, waned, and fluctuated in quality with the seasons.”
“When food was scarce, nilgai ate more browse, dead vegetation, and dry dung of large herbivores. The quality and quantity of their forage was within the levels published for cattle and North American big game. They maintained a feeding role intermediate between cattle, which used mainly grass, and deer, which used forbs heavily. When food supply and variety was low, nilgai competed strongly with cattle for grass and deer for forbs. The three species seem compatible where there is good variety of browse and herbage, and control of their respective numbers.”
While nilgai are not considered a worry for deer in terms of outright competition for food, there is concern about ticks. More specifically the cattle fever tick. Once considered eradicated in the United States it has found its way back with a large portion of nilgai on the Laguna Atascosca National Wildlife Refuge infected.
This has caused wildlife officials to conduct aerial shooting to trim the numbers and hopefully stop the spread of the potentially deadly (to cattle) tick. Deer also carry the tick and there is no wholesale culling of them so some local residents decry the helicopter harvest and most hunters do not mind the nilgai. In fact, most hunters don’t mind them at all.
—story by CHESTER MOORE