Migration is a great way to avoid winter temperatures. These great journeys are most notable in many birds, but also recieve attention in mammals including caribou and even people (Florida sure sounds nice at this time of year!). Unfortunately reptiles don't posses the wings or long legs (or airplanes) that often aid in those long distance travels. Our Ontario snakes, turtles, and lizard must make due with the temperatures that are available in the province over the winter. If we remember that reptiles are ectotherms (regulate their body temperature with their surroundings), it makes sense that those snakes, turtles, and lizard must do something to escape the air temperatures. The adaptation to freeze solid we learned about in the last posting are unique to Painted Turtle hatchlings, and Wood Frogs. So where do they go??
Hibernacula is a word describing one of these winter safe spots. Many animals use hibernacula, and the characteristics that make a "good" hibernacula will be different for different critters. For instance, bears can make due with a snow covered debris pile. But because reptiles don't make their own body heat, they can't just rely on the insulation of snow like the bears. They have to get their bodies below the frost line for the winter. I will go into more detail about turtle hibernacula next time, so today we will focus on terrestrial overwintering of snakes.
Snakes lack appendages (I'm sure you all knew that before!!), so digging to get below the frost line isn't a likely option. They have to make use of natural structures. Smaller snakes including the Redbelly Snake and Smooth Green Snake have been documented to spend the winter in abandoned ant mounts. Other species may crawl down crayfish burrows, and others might travel along corridors made in the ground by decayed root systems of large trees. Rocky areas also make great hibernacula, as the cracks and crevices in bedrock can extend down past the frost line. A good hibernacula could harbour many snakes of different species. However not all species overwinter with friends. Massasauga Rattlesnakes overwinter by themselves more often than with other snakes. I think one of the most famous snake overwintering spectacles occurs in Manitoba. Red-sided Garter Snakes (which cna also occur in the northwest portion of Ontario) overwinter in masses that exceed 10, 000!!! These overwintering masses are thought to help the snakes out in the spring during mating season. If they are all together, the males don't have to spend time looking for the females.
You can help out in reptile conservation locally by protecting areas that could be hibernacula for the local populations of snakes. You can also build your own hibernacula by digging large holes into the ground, filling them with rocky debris/rubble, and covering with a layer of earth. These can be fairly involved projects, so check with local regulations before you dig. Winter is such a hard time for our reptiles though, and they can use all the help they can get!
M.