These wood frogs can go all winter without peeing

May 2, 2018, 12:02 p.m.
Close-up of a wood frog
Photo: Dave Huth/flickr

For humans, it's a simple law of nature: when you gotta go, you should go. But if you're a wood frog, not only can you hold it for eight months, but it's the key to your survival.

That's the finding of a study published in the journal Proceedings of the Royal Society B. Wood frogs in Alaska go into a state of deep freeze, getting as cold as 0 F (minus 18 C), so it's understandable that they can't pee. To get through this frozen state and resume their lives as if nothing happened, the frogs recycle urea, the main waste in urine, into nitrogen. The recycled urea doesn't warm up the frogs. Instead, it protects the cells and tissues inside the body since nothing else provides that function at the time.

"This is stress that would definitely kill any mammal," one of the study's co-authors and zoologist at Miami University in Ohio Jon Costanzo told the Associated Press. "People are fascinated by bear hibernation, but in my book any animal that allows itself to freeze solid and is able to recover from it and walk away and thus go about its business like nothing happened, to me that’s about as cool as it gets."

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