Following on from the last couple of weeks of Froggy Friday posts, we will further explore ‘where frogs go’. So we know some frogs burrow, especially in the desert to avoid drying out. Well what about in cold or freezing habitats? The only place on earth frogs don’t occur is Antarctica, however, they do occur in alpine areas that become covered in snow in winter.
As we know, frogs are cold-blooded animals, which mean they can’t keep warm by themselves and they don’t have fur or feathers to trap heat. But some frogs have something else... anti-freeze! Just like the anti-freeze used in cars to stop water in car radiators from turning to ice. It’s called glucose or glycerine. The onset of freezing triggers a process where the liver produces high levels of glucose or glycerol that protects against freezing. Amazingly, as freezing progresses, breathing, heartbeat, and most other vital functions stop, but will start up again after a few hours of thawing.
Source: M. Tyler, ‘Frogs are Cannibals’; and Lane and Lee ‘Adaptations of frogs to survive freezing’ http://www.int-res.com/articles/cr/5/c005p053.pdf
The frog photo is of a well known freeze-tolerant frog the Wood Frog from north America. (Photo by: http://www.dogonews.com/2015/3/19/tiny-wood-frogs-survive-winter-by-partially-freezing-their-bodies)