As the length of daylight increases and temperatures begin to warm, ectotherms — animals that cannot regulate their own body temperature — will begin to emerge from their winter refuges. Hibernation (or brumation) is how reptiles avoid dying in freezing temperatures and surviving in a landscape where conditions are not warm enough the entire year.
Reptiles are not able to regulate their body temperature internally, as they cannot generate body heat. They need an external source of heat to bring their body temperatures to levels where basic activities can occur, such as foraging, digestion of food, basking, shedding, mate searching, and gestation.
Generally, reptiles require two features for survival during their inactive season: refuge from freezing temperatures and an oxygen supply.
Even though most turtles are found in close association with water, not all turtles burrow into the mud below water to survive the winter. Most do, but box turtles overwinter in deciduous forests below the frost line in the soil.
Also, not every water supply may be adequate for overwintering. During overwintering, different species of turtle have different levels of tolerance to hypoxic (low oxygen) conditions. Snapping turtles (New York State’s official reptile) can endure almost complete oxygen deprivation for extended periods of time, whereas wood turtles need a constant supply of dissolved oxygen in the water to survive the winter.
An excellent example of overwintering flexibility can be found in the timber rattlesnake, where here in the North, the species require rocky ledges and talus slopes to survive the winter. Conversely, in the south they may be almost completely submerged at or near the water table during the winter months.
Photo: Painted turtles basking on a log by D. Arlene Bonnett (provided by DEC).
