How Woody Survives The Winter

There are many oddities in this world: mammals that lay eggs, genetic mutations, but our main focus today is that of the cryoprotected frog. Most reptiles and amphibians must find certain ways to survive the cold winters, burrowing into the ground to keep warm, but these strange arctic wood frogs are the outliers. Certain frogs like Rana Sylvatica can freeze two thirds of their body completely to last the winter, and go for many weeks doing so. During this time, their brains can stop as well as their hearts. These little wood frogs can freeze at 3.2 degrees Fahrenheit and still manage to be revived when they thaw. It is believed that they can even go past this point, depending on the particular frog's endurance.

How are they able to do this and not die? It is noted that they have certain cryoprotectants, large amounts of glucose and urea, which protect their cells during 'hibernation'. Most animal's cells, when faced with extreme cold, will shrink to a point that they loose all nutrients and die. However, these cryoprotectants resist shrinkage, keeping the frog alive.
Wood frogs are generally small, reaching about 2 inches. They have the same coloring as the wood they are named after -generally varying in shades of brown. Rana Sylvatica can be distinguished by their dark eye mask as well as a white stripe just above the lip. They lack webbing on their back feet, contradictory to most frogs, but that makes them ideal for tree climbing. They are insectivores and herbivores, surviving on invertebrates and pond algae.

Baby wood frog

These frogs are currently studied for medical purposes. Doctors hope to find a way to cryogenically freeze humans (probably to save Walt Disney).

Links: http://voices.nationalgeographic.com/2013/08/21/how-the-alaska-wood-frog-survives-being-frozen/