Could a cobra or a viper survive the winter using their bodies brumation method of hibernation?
The First Dragon
Rattlesnakes are vipers, so the answer is yes for vipers. Probably not all vipers. I read that king cobras don't hibernate or bromate, but there are many species of cobras. I imagine some of them do.
Yes, and they do so routinely. All extant species of cobra are native to tropical and subtropical desert regions, and therefore rarely need to brumate. But captive specimens in temperate zones can go into brumation mode whether they need to or not.