With Winter Coming, Frogs Play it Cool

American toad

During the winter, amphibians such as the American toad burrow deep into the soil, safely below the frost line. (Photo by Brian Gratwicke, Smithsonian Conservation Biology Institute)

I have always had a bit of a fetish for frogs and toads. I have a number of toads in my back yard every year. One has taken up residence under my grill for at least three years now.  My two terriers are great fans of this little guy!

Now that it is getting colder, I have been wondering what actually happens to these guys once the cold weather settles in.  So I did a little research.

While most of us would pack our bags and move to Florida, that’s a pretty long way to travel for frogs and toads. So instead, they find a living space called a hibernaculum that will protect them from weather extremes and predators. They “sleep” away the winter by slowing down their metabolism; their heartbeats and breathing slows and their body temperature drops to nearly match the outside temperature as they pass the time in a state of dormancy. When spring arrives, they wake up and leave the hibernaculum, immediately ready for mating and eating! I guess they are pretty energized after that long winter’s nap!

Different species of frogs and toads have different strategies.  Northern leopard frogs, for example, pass the winter at the bottom of deeper lakes, far beneath the ice. They settle on the lake bottom in deep water and stay concealed behind a log or other debris to escape predators.

Aquatic frogs hibernate under water and take in oxygen from the water through their skin. They spend most of the winter lying on top of the bottom’s mud or partially buried in mud. At times, they may even slowly swim around.

Terrestrial frogs and toads typically hibernate on land. Those frogs and toads that are good diggers, such as the American toad, burrow deep into the soil, safely below the frost line. Spring peepers are not adept at digging so they find deep holes or cracks in logs or rocks, or simply burrow down in the leaf litter as far as they can to stay protected.

A few species that live in especially cold climates can even survive being frozen solid.  Check out this video I found of a wood frog going through the freeze/thaw hibernation process. Amazing!

If you have a pond frequented by frogs and toads in your back yard, put some leaf little in it so they can nestle down for a good slumber.

So as we say goodbye to these wonderful amphibian creatures for the year, keep your fingers crossed that it will be an easy winter.

To learn more about hibernating frogs and toads, check out the following web sites:

http://www.learner.org/jnorth/search/FrogNotes3.html

http://warnell.forestry.uga.edu/service/library/wg-25/index.html

http://frogsaregreen.com/4172/winter-is-coming-how-do-frogs-avoid-freezing/

Cindy Hoffman, Defenders of Wildlife