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.