6. Wood Frog
How would you like to go into a cryogenic state while the hard winter blizzards storm above? Go ask the wood frog, a native inhabitant of the extreme cold environments of Northern Canada and Alaska. During the coldest of winters when temperatures are subzero, the wood frog can go into hibernation with no heart or brain activity, coming back to life when temperatures begin to warm up. The frog’s liver produces high amounts of glucose that act as antifreeze so that organs are ready to come back to life as soon as temperatures allow.