How Do Frogs Breathe During Hibernation?

Outside of times of hibernation, frogs usually take in oxygen via the air, employing their lungs. The vast majority of frogs that go into hibernation continue breathing the whole time, although there are a handful of exceptions. Some frogs are capable of staying alive even while stopping breathing entirely. Not only do they cease breathing, their hearts stop, too. The wood frog (Rana sylvatica) is one example. These amphibians can manage between two and three months in this frozen manner. Once temperatures rise again, they start breathing as if they never stopped, and their hearts proceed as before.

Frogs aren't restricted to breathing only through their lungs. Frogs that spend the coldest times of the year inside of the mud or within rotten heaps of leaves receive their necessary oxygen through their skin. This is referred to as cutaneous gas exchange. They use their skin to soak in the oxygen their bodies require. When frogs hibernate, they utilize the skin for any and all breathing. Damp skin is a must for subcutaneous gas exchange. If a frog's skin becomes dry, it will no longer be able to take in oxygen.

When frogs opt to retreat to the water for the winter, it's important that they choose conditions that are appropriate for hibernation. Water with sufficient oxygen is imperative. In the wintertime, they occasionally even move around in the water as a way of sustaining adequate amounts of oxygen. The kinds of aquatic environments frogs gravitate to for hibernation include ponds, lakes, creeks, streams and springs.

Water intake in frogs is similar to their breathing during hibernation. Just as they take in oxygen through their skin, they take in water the same exact way, never through their mouths. Their water travels into their bodies through their "drinking patches," which are situated below their thighs and on their stomachs.