Snakes cannot regulate their body temperature, so they depend on the climate temperature to do it for them. Snakes hibernate in any climate where temperatures drop below freezing for long time periods. In warmer places like Arizona, snakes don't hibernate as long as they do in colder climates, but they also go into summer hibernation to protect themselves from extreme heat and food shortage. Almost all Arizona snakes hibernate at some point.
Common Arizona Snakes
Arizona has a wide variety of snakes classified by their appearance, distribution, habitat or venom capabilities. Rattlesnakes,Gopher, Coral and King snakes typically avoid moist habitats, so Arizona's dry deserts, mountain areas and light woods provide an appropriate home for them. Gopher snakes hibernate during the harshest weeks of Arizona's winter and summer, during the night and day, respectively, depending on the part of the state. Aquatic garter snakes also live in Arizona's rivers, ponds and cattle water tanks, at times.
Where They Hibernate
Snakes typically don't store up fat before hibernating, as mammals do, because their body temperatures aren't regulated metabolically, like mammals. Snakes find dens in hollow tree stumps or, especially in the Arizona desert where land is often open and sparse, in holes in the ground or underneath rock piles, like rattlesnakes. Dens are typically located near sunny spots, usually on a south-facing slope. Since these spots are rare in the Arizona desertscape, 100 to 200 rattlesnakes may live in the same den. Snakes return to the same den each year, even baby snakes who've never been to the den, perhaps following scent trails from fellow snakes.
Snakes go into a state called "torpor" during hibernation. Where mammals store food and slow their metabolic rate during hibernation, snakes simply go into a slow, lethargic state, not feeding or mating during the winter months. However, Arizona's typically warm, sunny winter days attract the snakes to come out and warm in the sun for several hours, usually on warm rocks.
In hot areas like Arizona, certain desert snakes, like rattlesnakes, go into a summertime torpor, or aestivation. The snakes burrow underground during the hottest summer weeks, when temperatures sore well between 100 and 120, depending on the location and time of year. Cottonmouth snakes also aestivate during the hottest, driest weeks when prey is scarce. Snakes may come out during the evening when temperatures are bearable, as the Arizona gopher snake does.