Snakes are cold-blood animals, which means they can't make their own body heat and thus their body temperature is determined by the surrounding air temperature.
Large constrictors like pythons and boas are tropical snakes that require external temperatures at least higher than the mid-70s at the lowest, and often above 80 degrees F.
As you can see by the winter weather map below, there are not many places in the U.S. that maintain those average temperatures year round.
Thus, based on this map, it is clear that large tropical constrictors cannot live year-round outside of handful of south eastern states, and thus cannot maintain permanent populations outside of these areas.
As you can see, Texas is not one of those states where they can thrive.
People keep these animals as pets in all climates (although anyone who keeps a snake longer than 8-10 feet is nuts, in my opinion), and often release them when they get too big. So that can happen in any state. But these snakes generally will die as the weather gets colder.
