The proper term for a reptile is brumate, or brumation. Many species don't do this naturally either way. And most species from colder climates that do in the wild, do not need to if they are given ideal conditions year round. Many people do reduce their temperatures during the winter to encourage this natural behavior anyways. Some bearded dragons will go into a form of brumation no matter what you do with lights and temperatures, while some never do. For allot of snake species, it is necessary to brumate them to encourage proper breeding, so that is an additional consideration.