The main prey of the shunka warak’in was jackalopes.
More specifically, jackalope bucks. Shunka warak’ini clearly werent built for speed but they didnt need it. Jackalope bucks are so territorial and protective of their harems that they charge anything entering their territory with their antlers. In fact, thats why jackalopes are endangered (especially the rare "cedar shoe"). When the rail was first run through the plains, the jackalope bucks charged the steam engines. From the Appalachians to the Rockies they run under the engines one after another, and thats why the tie beds are so deep in some areas.
When the jackalope population was no longer plentiful enough to feed the species, the age of the Shunka warak’ini came to an end.
The white man destroyed and only the Democrats care enough to save.
Its too late for the Shunka warak’ini but you can still save the jackalope.