This Alaskan Frog Freezes Solid and Comes Back to Life

Imagine disliking winter so much that you appear to die when it begins, only to come back to life in the spring. That’s essentially what the incredible wood frog does (well, almost) to survive the brutal Alaskan winters. You can watch the frog freeze and then thaw out in this fascinating video clip. In this article, we explain how wood frogs survive this process and why they go to such extremes.

Surviving the Alaskan Winter

The northern forests of Alaska experience icy cold winters. It is not unusual for them to experience temperatures of minus 50 degrees Fahrenheit, and the state’s all-time record low is minus 80 degrees Fahrenheit. The wood frog is found throughout the forests of Alaska. They live amongst the leaf litter and feed on insects, arachnids, worms, slugs, and snails. As temperatures plunge, this cold-blooded creature is not able to. Furthermore, the animals it usually feeds on are in short supply or have disappeared. So, it basically decides to sit out the winter! It’s not unusual for frogs to hide away at the bottom of ponds in winter, where they enter a dormant state. It’s very cold down there, but crucially, the water inside their bodies does not freeze because it is warmer underwater than on land. Wood frogs, however, take it a step further.

Frozen Wood Frogs

When temperatures fall, wood frogs hide away in leaf litter. The temperatures here are cold enough to freeze the water inside their cells. This is dangerous because freezing water disrupts the integrity of the cells and kills them. It also punctures blood vessels. However, inside the wood frog’s body, ice fills up the abdominal cavity and surrounds their organs. At the same time, this ice creates a layer between the skin and muscles. Their liver produces a special sugar solution that acts like an antifreeze. It enters every body cell, binds to the water molecules, and prevents them from freezing.

Is This Hibernation?

This state is not the same as hibernation. In this frozen condition, the wood frog’s heart does not beat, so there is no circulation. Their muscles do not move, and they do not breathe. If you come across one, it will look like a lump of ice in the shape of a frog. Because leaf litter warms up more quickly than ponds, wood frogs can become active earlier in the season. As temperatures rise, the ice in their bodies melts, their hearts restart, and they move around. Soon, they are hopping around, searching for a pond to breed in, with no apparent damage from their time spent in a frozen state.