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UAF Researchers Look at Alaska Frogs that Survive Extreme Cold

Canadian Geographic

Researchers studying wood frogs have discovered the little vertebrates are able to survive incredibly cold temperatures.  

Alaska’s interior is home to wood frogs.  These amphibians create a hibernaculum, or a shelter occupied during the winter.  These shelters can sometimes remain at temperatures below freezing for more than six months with minimum temperatures of minus four degrees. 

University of Alaska Fairbanks graduate student Don Larson says the frogs his report focused on lives from West Virginia to past the Arctic Circle.  He says it was known that these frogs could survive brief periods of freezing with ice forming around their cells.

“They do this by two things, they make urea, the stuff we pee out and they also convert sugar in their liver and pump glucose all around their body. They put the sugar in their cells to prevent any damage from ice forming and to help their cells survive winter.”

Larson says the reason he wanted to look at these frogs is because the common scientific belief was that wood frogs could not survive very long frozen and not at very low temperatures.  The researchers tracked frogs with radio transmitters in the wild, frogs in an enclosed area at UAF and lab frogs.   

“What we found was wood frogs in Alaska are much heartier than we predicted. Wood frogs last longer, they lasted almost seven months frozen, to lower temperatures, negative 20 Celsius and they all survived. So in the lab when we tried to replicate these studies we had massive die off. But with our wood frogs we had high levels of survival and they had more chemicals that they use to survive in our frogs outside than we’ve ever seen in lab frogs. 10 times more sugar in our frogs in Alaska than our laboratory frogs.”

The implications, Larson says, definitely cross over to humans.  The study of how these frogs are able to survive the cold for so long could help with organ transplants and, in the long run, cryogenics.