This article is over 5 years old and may contain outdated information.


Biological antifreeze frog’s friend for winter

Wood frog breaks down skeletal muscle mass to survive winter
  • Nov 30, 2013
  • 254 words
  • 2 minutes
Expand Image

Most animals bulk up in preparation for winter, but not this one.

In a recent study published in the Journal of Experimental Biology, biologists found the common wood frog actually survives harsh winter temperatures, in part, by breaking down its skeletal muscle mass.   

“No other scientists have really looked at the changes in the physiology of this frog in the period leading up to winter,” says John Costanzo, a professor of zoology at Miami University, in Oxford, Ohio, who co-authored the study.

The wood frog is one of the most widely ranging amphibians in North America and is native to all Canadian provinces and territories, even existing above the Arctic Circle.

To survive winter weather, wood frogs build up cryoprotectant solutes in their blood months before winter arrives. These solutes, which are mostly glucose, glycogen and urea molecules, allow the frog to lower the freezing point of its blood, preventing ice from forming in its cells — a condition which could be lethal. “We were surprised to find that the frog is able to accumulate urea by degrading some of its muscle protein,” says Costanzo.

What was even more surprising for Costanzo was how wood frogs in Alaska were better prepared for winter than wood frogs found in Ohio. Lower-latitude Ohio frogs could only tolerate winter temperatures as low as –5 C, whereas Alaskan frogs managed –16 C. The Ohio frogs did have the cryoprotectant urea in their blood stream, but not to the same extent as the Alaskan frogs.


Are you passionate about Canadian geography?

You can support Canadian Geographic in 3 ways:

Related Content

illegal wildlife trade, elephant foot, ivory, biodiversity


The illegal wildlife trade is a biodiversity apocalypse

An estimated annual $175-billion business, the illegal trade in wildlife is the world’s fourth-largest criminal enterprise. It stands to radically alter the animal kingdom.

  • 3405 words
  • 14 minutes
A grizzly bear lies dead on the side of the road


Animal crossing: Reconnecting North America’s most important wildlife corridor

This past summer an ambitious wildlife under/overpass system broke ground in B.C. on a deadly stretch of highway just west of the Alberta border. Here’s how it happened.

  • 3625 words
  • 15 minutes


Do not disturb: Practicing ethical wildlife photography

Wildlife photographers on the thrill of the chase  — and the importance of setting ethical guidelines 

  • 2849 words
  • 12 minutes


Canadian Museum of Nature welcomes colourful frogs

As some of the most visually stunning, vocally amusing and biologically diverse animals on Earth, frogs play an integral role in ecosystems around the world, from boreal forests…

  • 625 words
  • 3 minutes