Have you ever wondered how turtles survive the Winter, when lakes and ponds freeze over? What do they do to stay alive? We all know that lungs don’t work under water. While turtles can hold their breath for quite a while when submerged, clearly, they can’t possibly do it for several months.

No, the smart ones don’t buy plane tickets to Florida. They don’t spend the Winter hibernating in caves like bears and bats. So, what do they actually do?

It’s called brumation, and while it’s somewhat similar to hibernation, it’s actually far more complicated than that. In fact, it’s pretty amazing. Let’s learn a little more about brumation.

Most of us are familiar with hibernation. Animals that hibernate are able to slow their metabolism enough to enter a deep sleep state and live off their stored fat reserves. If protected from the weather and covered with enough insulation, they can stay warm and survive until the Spring thaws.

Brumation also involves a lowering of the metabolic rate. Unlike hibernators that continue to breathe air, some turtle species are able to handle low oxygen conditions by converting over to “breathing” through their skin while under water, instead of through their lungs.

They can absorb oxygen through their legs, cloaca (anus), and the lining of their mouths. Turtles that only “breathe” through their skin during brumation must locate in areas where oxygen is rich in the water, such as near inlets to ponds.

Some species of turtles are able to also use other chemical pathways that don’t require oxygen to process stored reserves of energy. How can I describe that? Humans are actually able to do the same thing.

If you use your muscles vigorously, your body directly breaks down sugar for extra energy without using oxygen. In addition to breathing and having carbon dioxide as a waste product, your body produces lactic acid in your muscles from the sugar breakdown. This acid buildup is why your muscles get sore.

The same buildup of acid byproducts occurs in the turtles. Some species, like the painted turtle, are able to liberate calcium carbonate from their shells. Just like how an antacid tablet works, the calcium carbonate helps to neutralize the acid buildup so that the turtles can survive.

Hibernating animals can get a break during a mid-Winter thaw. Not so for our turtles during brumation. The temperatures at the bottom of the lakes and ponds where the turtles go to prevent freezing remain constant. Only the Spring ends the long marathon nap of the turtles.

Old Kermit the Frog always says, “It’s not easy being green.” It’s actually not too easy being a turtle either. Only the strongest are able to endure brumation.

Let’s all enjoy the outdoors!