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Frog that freezes itself during the winter

MrChad

Lifer
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This is the way a wood frog freezes:

First, as the temperature drops below 32 degrees, ice crystals start to form just beneath the frog's skin. The normally pliant and slimy amphibian becomes -- for lack of a better word -- slushy.

Then, if the mercury continues to fall, ice races inward through the frog's arteries and veins. Its heart and brain stop working, and its eyes freeze to a ghostly white.

"Imagine an ice cube. Paint it green," and you've got the wood frog in winter, said Ken Storey, a professor at Carleton University in Ontario. The frog is solid to the touch and makes a mini-thud when dropped.

But it is not dead. When a thaw comes, the frog is able to melt back into its normal state over a period of several hours, restart its heart and hop away, unscathed.

Cool stuff 🙂
 
I wonder if you dropped one of those frozen frogs into a container of liguid nitrogen if he would still be able to thaw after that. 😀
 
Originally posted by: ElFenix
how does it keep the ice crystals from rupturing cellular structures?

From the article (page 2):

Scientists say that, before winter comes, the frogs eat ravenously, storing a starch in their livers. A freeze triggers their bodies to convert the starch into other compounds, most often glucose, or blood sugar. The frogs become, in essence, extremely diabetic.

The glucose lowers the freezing temperature of water inside the frogs' cells, and because of this, the cells stay liquid, even as ice fills the space around them. This is crucial: If the water inside the cells froze, scientists say, the jagged ice crystals would destroy everything inside, killing the frog.
 
Originally posted by: MrChad
Originally posted by: ElFenix
how does it keep the ice crystals from rupturing cellular structures?
From the article (page 2):
The glucose lowers the freezing temperature of water inside the frogs' cells, and because of this, the cells stay liquid, even as ice fills the space around them. This is crucial: If the water inside the cells froze, scientists say, the jagged ice crystals would destroy everything inside, killing the frog.

Wait a minute, extracellular fluid?
 
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