In one of the strangest ways to live through the winter, the Alaskan wood frogs simply let themselves freeze into a block of ice for seven months. They are not frozen completely solid, but two-thirds of their body turns into ice. And if you bent their legs they would snap like ice.
So they are effectively frozen solid during the winder, if you pick them up they will not move at all. And research has shown that there are many strange things happening to their body during this process: their heart actually stops & blood no longer flows. If you look at from an organismal level, they are actually dead. The individual cells in the frog’s body are still alive, but they stop communicating with each other.
And the craziest thing that comes out of this frozen state? When Spring arrives they easily thaw out and hop away. Biologists have known about the freezing frogs during winter for decades and believe it has to do with their glucose levels. When this process happens the frog’s glucose levels skyrocket up very high, which lets them tolerate extremely cold temperatures seen in Alaska.
To figure out how the frogs were surviving so long in a frozen state, researchers stuck mini radio transmitters to their backs to be able to monitor a group of Alaskan wood frogs for 2 years. Once the frogs were frozen and settled they placed a little cage over their spot and started to record their temperatures at regular intervals. The amazing thing is over the course of the study none of the frogs died off, meaning these frogs have mastered how to survive the cold.
It is the glucose levels that are key, they allow water to be kept inside cells, frostbite happens when all the water in a cell becomes ice. Which in turn causes cells to dehydrate and die. Having high amounts of glucose, keeping everything super sweet, stop this from happening and keeps the frog’s cells alive.