Is This a Frozen "Alaskan Tree Frog"?

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Alaskan Tree Frog

Alaskan Tree Frog Hoax
Viral image purports to show an "Alaskan tree frog," which allegedly freezes in the winter, stopping its heart, then thaws and revives in the spring. Viral image, original source unknown

Description: Viral image / Hoax
Circulating since: 2013?
Status: Mislabeled (details below)

Caption example #1:

Alaskan tree frog. Freezes solid in winter, thaws in spring and hops off

Caption example #2:

This is what an Alaskan tree frog looks like. It freezes in winter, stopping its heart, then thaws in spring.

Caption example #3:

the Alaskan tree frog freezes and stops its heart rate completely. Thaws and comes back to life again when the conditions become favorable

Analysis: Sorry, enthusiastic sharers, but the whimsical specimen in this photograph doesn't appear to be a real frog at all, much less a "frozen Alaskan tree frog." More likely, it's an iced-over ceramic garden ornament. Cute photo, to be sure, but circulating under false pretenses.

There is, in fact, no such species as an "Alaskan tree frog" — none that I could find in reference books on amphibians, at any rate — though it's true that scientists have identified a diminutive species named Rana sylvatica (commonly called a wood frog), that can survive Arctic temperatures for months at a time with up to two-thirds of its bodily fluids frozen solid.

"Alaska wood frogs spend more time freezing and thawing outside than a steak does in your freezer and the frog comes back to life in the spring in better shape than the steak," says University of Alaska Fairbanks grad student Don Larson, the lead author of a recent study on the freeze tolerance of the Alaska wood frog.

How does the species accomplish such a feat, given that the freezing process normally damages and kills living tissues (think frostbite)? By overdosing on sugar, apparently. Researchers have discovered that wood frogs' bodies prepare for the coldest winter months by "packing" their cells with glucose (blood sugar), which acts as a "cryoprotectant" to prevent tissues from drying out and collapsing when the water they contain turns to ice. According to Larson, wood frogs tracked in the wild proved able to endure below-zero temperatures for as many as 218 days straight with a 100 percent survival rate.

Larson and co-author Brian Barnes believe their research may ultimately serve a more practical purpose, namely indicating ways to improve and extend the preservation of human organs for transplantation.

Thank you, wood frog!

Sources and further reading:

Rana Sylvatica (Wood Frog), 7 February 2015

Wood Frog
National Park Service

Alaska's Frog
Alaska Public Lands Information Center

Alaska Frogs Reach Record Lows in Extreme Temperature Survival
Institute of Arctic Biology/Univ. of Alaska Fairbanks, 22 July 2014

How Arctic Frogs Survive Being Frozen Alive, 21 August 2013