This is called a “behavioral fever,” and it’s been documented in tortoises as well. It may have some kind of bacterial infection, so it’s forced to come out and bask to keep its temperature elevated, fight off infection, and maintain the healing process. The other is that the snake might be sick. We’re not quite sure why that is, but I have found it to be much more common to see young snakes out during colder weather than older, mature snakes. The first is that it will mostly likely be a juvenile. If you do see a snake out in the winter, it’s usually one of two things going on. And then, eventually, when they give birth, it’ll be right around monsoon season, when there are more prey resources. When they come out of the den in the spring and warm up, they can develop eggs that are then ovulated and fertilized by the stored sperm.įemales come out of the dens earlier than males because they want to get their ovaries warmed up and get follicles to grow enough so they can be ovulated. In fact, females who have mated the summer before store sperm from the males over winter, during hibernation. For rattlesnakes, winter triggers hormonal changes that allow them to become reproductively active, so they actually need the cold to allow them to produce certain hormones that are important for reproduction. Warming of the climate could change the time of year when snakes go into their dens-called ingress-and when they come out-called egress.Ĭlimate warming could affect the cues that cause rattlesnakes to come out of their dens, because if warmer temperatures tell them it’s time to come out, they’d end up coming out sooner, which may increase the risk of exposure to cold spells or may not coincide with when their prey are more active.Ī warming climate could change the timing of their reproduction, as well. This is a very important question for people who study snakes and other reptiles that live in temperate climates, where hibernation is the rule. There’s some debate on whether we should call it “hibernation” or “brumation,” which is essentially hibernation in ectotherms, but for our purposes it’s OK to call it hibernation, or a period of winter inactivity. Western diamondback rattlesnakes, a larger, more common species, will go into their dens a little later, on average.įor the most part, around Tucson, at this elevation and with the winters we have, almost all reptiles undergo a hibernation period. One species that I have studied extensively is the tiger rattlesnake, which is a smaller, retiring species that tend to go into their dens from late October to early December.

That said, the timing and length of the overwintering period varies by species. They will stop feeding and enter into a sometimes long period of inactivity. Rattlesnakes are very long-lived-about 15 to 20 years, or more-relative to their body size because they’re really good at conserving energy. As it turns out, being an ectotherm has some advantages, like being able to essentially shut down your system and save energy rather than spending it on trying to stay warm. When winter temperatures get too cold, snakes typically go underground or into natural shelters, like rockpiles or mammal burrows, to avoid freezing. Therefore, snake body temperatures are coupled with environmental temperatures, although they are very good at behaviorally thermoregulating to keep their body temperatures fairly constant. Snakes are ectotherms, which means their internal body temperatures do not remain constant like mammals, which are endotherms.

Do snakes hibernate in winter