swopjan, think "exotics". Quite a few non-native game animals on Texas ranches. E.g., the King Ranch has IIRC over 10,000 nilghai, some saying that's more than remain in India.
There is a small oryx herd on the 02 ranch south of Alpine, in the 100,000-acre "east pasture". They sometimes hang out near the highway fence, counting cars.
Axis deer have spread from original locations, as have aoudad. And, to a lesser extent, blackbuck antelope.
Other than for aoudad in the Texas Panhandle, it's open season on these ferals. They are thus a source of income outside of our usual deer seasons.
There is a slow growth in the population of elk which are not native to Texas. SFAIK, those brought in from the Rockies are a different sub-species than the extinct Texas elk. By law, they are feral. It's thus up to a rancher as to when and how they are hunted.