I know this is fiction but here is my understanding. I am unfamiliar with dune, but as for tatooine, it was once far more earthlike, with liquid water oceans, which is the environment in which life would have evolved there. There was some kind of ecological disaster there, not a natural disaster, by some accounts caused thousands of years before the events of the movies by the fall of a society called the rakata. It lead to a mass extinction event which very few species survived. As far as I know, there are six species that may be indigenous to tatooine, the Krayt Dragon, the Saarlac, the Jawas, the Tuskens, a species of black desert melon that live under the sand, and an unnamed many limbed large and mostly subterranean predator that can be seen in the show The Book of Boba Fett. The bantha may be native though I doubt it. All are adapted to desert life and are very hearty. Several spend much of their life under the surface of the sand or in caves to protect them from the very harsh environment
Facebook
Twitter
Instagram