Where Do Turtles Go in Winter?
We always take note of the turtles we see in the spring digging nests in the sand along our shorelines or roads, but what are they doing right now?? Where and how do they spend the winter? We certainly have an abundance of turtles in the Flowage.
Eleven varieties live in Wisconsin, and the two types we see in the Flowage are the painted turtle and the snapping turtle. Ten of these varieties hibernate at the bottom of water bodies rather than on land because water has the ability to absorb heat with only a minor increase in temperature. When the water temperature goes below 39 degrees F, the cooler water rises and the turtle never reaches the point of freezing. They have temperature stability. However turtles still have a need for oxygen.
Turtles have two sources of oxygen: a throat cavity, and two thin-walled sacs near the anus which are lined with minusulce bold vessels that permit oxygen to be extracted from the water. In addition, their slowed metabolism allows them to last for longer periods. A turtle’s metabolism is already ten times lower than other warm-blood mammals, but during hibernation, it drops another 10 – 20 percent. In winter their heart rate drops to one beat every ten minutes. Finally, so that lactic acid does not build up in their muscles due to inactivity, calcium salts from their shells gradually dissolve into their blood stream to neutralize the lactic acid –and keeps their hearts pumping and active.
With all of these special abilities, turtles are truly another marvel of nature.
—from an article by Kim Shankland, UWSP student in Lake Tides, published by the Wisconsin Lakes Partnership