Most people picture snakes as creatures of warm, humid jungles or sun-baked deserts, and for the vast majority of the roughly 4,000 known species, that’s exactly right. But a handful have pushed the boundaries of where a cold-blooded animal can actually survive, turning up in conditions that seem almost designed to kill them, like deserts hot enough to cook an egg on the sand, and terrain so far north that snow outlasts summer. Since snakes can’t generate their own body heat, each extreme demands a genuinely clever survival strategy rather than just tolerance. Here are five species that have figured out how to not just endure harsh climates, but actually thrive in them.