Biology: winter survival

The tutor shares a fact that surprises him.

Winter here is fairly mild; I think the mean daily temp in Jan might be around 5 deg Celsius, with the mean nightly low being around -1 deg Celsius. That being said, this place is a rarity in Canada; even places further south than here, but east of the Rockies, are typically much colder. For places both east of the Rockies, and north of here as well, winter might as well be spent in a deep-freeze. How do the animals living there cope with it?

Recent reading informs me that some amphibians – e.g., frogs – actually freeze solid during winter as a survival mechanism. The wood frog and chorus frog are two examples given.

I’ve spent time around Prince George and know that, in May, the temp can reach 15 deg Celsius during the day but still plunge to -5 deg Celsius at night. In spite of the hard nightly freeze, flies abound in forest clearings. They must, I’ve always suspected, freeze at night, yet thaw the next day and live on. This Biology text confirms my suspicion. However, I wouldn’t have known for sure that frogs could do so as well.

To me, the point is surprising, yet makes a lot of sense. After all: how could those frogs avoid freezing solid through weeks in Jan or Feb, during which the temperature may not climb above -5 deg C, and certainly plunges below -20 deg C most nights?


Ritter, Bob et al. Nelson Biology. Scarborough: Nelson Canada, 1996.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

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