The forest frog, the only frog living north of the Arctic Circle, freezes in the winter and thaws in the spring to continue its life.
The forest frog is the only frog that lives north of the Arctic Circle.
It is a frog that has the power to survive in freezing temperatures, thaw and come back to life. Animals have developed different methods to survive in cold winter conditions. Some migrate to the equator for summer vacation, while others hibernate underground to escape freezing temperatures at the surface.
But forest frogs just freeze and wait for warm weather to come again. The forest frog species called rana sylvatica can withstand temperatures of 2.5 degrees below zero. Scientists discovered that these palm-sized amphibians go through daily freeze-thaw cycles. They freeze at night when the temperature is low and thaw during the warmer days.
This antifreeze property comes from the way their bodies metabolize glucose. Normally, in very cold environments, the water in the cells of most animals flows out of the cells and turns into ice. This dries out the cells and eventually causes the death of the animal.
However, the forest frog has such a biology that when the freezing process begins, its liver goes into overdrive, converting stored glycogen back into glucose and pumping the glucose into thirsty cells.
The high glucose level in the cells prevents the water from turning into ice and keeps the frog frozen until the ice melts. The glucose is then metabolized into energy or stored back as glycogen.