Where Have All the Reptiles Gone?
Discovery Place Science
Have you ever wondered what happens to all the reptiles during winter? As the days grow shorter and colder, the lizards, snakes and turtles seem to disappear.
Reptiles are ectothermic, which means they need outside sources of heat to warm their bodies. In winter that can be difficult to do, so reptiles have different strategies to make it through the colder months.
As the days grow shorter, circadian rhythms, the same forces that make you sleepy when it gets dark out, tell reptiles that it is time to prepare for winter. For land reptiles this means finding sheltered hiding spots.
Many reptiles enter a hibernation-like condition called brumation. Within their winter hideaways brumating reptiles slow their metabolism, heart rate and breathing until their bodies almost stop. However, brumating reptiles will sometimes awaken and move around, especially on unseasonably warm days.
To better retain heat some snakes brumate together in caves or crevices called hibernacula. Box turtles brumate in burrows or deep under insulating leaf litter. On the coldest days when the chill reaches deep into the ground they can mostly freeze for several days without injury.
Not all reptiles live on land though. Many aquatic turtles spend the winter under ice and water. The tops of ponds and wetlands freeze, but below the surface the water insulates against the cold. In pools with plenty of dissolved oxygen, turtles at the bottom absorb oxygen directly through the skin under their tail near their cloaca.
In pools where there is not much oxygen, turtles survive by burning energy reserves. Without oxygen, lactic acid builds up in the body just like when you run and get a cramp. Calcium from a turtle’s shell neutralizes the acid, but turtles will go to the surface to get a breath of fresh air and detoxify if the ice thaws.
Longer days and warming temperatures signal spring for the brumating reptiles. When it is warm enough, they will wake up, emerge from their shelters and enjoy the spring sun. Until then, happy brumation to all the reptiles out there!