Dear Chris, they survive because they can find the best temps/shelters available. They go underground, within walls, use insulation etc. to keep warm or cool as they require. They are called House mice, because they have followed European man worldwide, living in peoples houses, barns,ships, man made shelters.
As FR and others have told us, we must give our kingsnakes options on microclimates, hot and cool, dark and light, etc. Let them choose, they will if he provide options. Similar to kingsnkes, The mice do this on their own, but when confined to a breeder cage in a 90 f garage, they don't have as many options as they would like. Hence, many of them do not thrive when it is hot, mine consistently quit breeding during the hot Summer. Commercial breeders often control temps with AC. vic h.