We watched with thermal cameras as they woke themselves up with a hangover of epic proportions.
As winter approaches and the temperature drops to -30C across parts of Canada, the thirteen-lined ground squirrel nestles one-metre underground in a grass-lined burrow for six months of the year.
It avoids the harsh weather and lack of food by slipping into a deep sleep known as torpor.
Its body temperature plunges to just a few degrees above zero, its heart barely beats, and it hardly breathes. This ground squirrel appears dead to the world.
It would be too dangerous to remain torpor all winter, so these squirrels re-warm themselves every ten days or so to maintain brain function and sleep. They need to wake-up to sleep! We watched with thermal cameras as its body warmed in real time.
As the brain begins to warm up, the squirrel shivers — a way to increase blood flow to almost frozen muscles and organs.
Like waking up with a hangover of epic proportions, the squirrel has temporary brain damage and suffers from memory loss and disorientation. It takes 30 minutes to become fully functional again.