We might see tracks of squirrels and birds in search of food on a fresh blanket of snow, but what are the animals hiding beneath the ground doing to survive? Many creatures hibernate to escape winter’s grasp. The first animal that comes to my mind is the groundhog. We celebrate Punxsutawney Phil when he emerges from his slumber to tell the weather ahead. Most cold blooded animals hibernate to survive the dipping temperatures. Many species of invertebrates lay the next generation’s eggs on twigs and leaves before the adults die at the first hard freeze. The invertebrates that overwinter as adults will go into a state of hibernation called diapause.
Brumation is when reptiles and amphibians reduce their metabolic process. The American toad and many land dwelling frogs dig holes below the frost line before entering brumation. The amphibians who are not able to dig a deep enough hole, hide beneath the leaves, under a log, or in cervices of rocks.
How is it that they survive when the snow falls? Will they not freeze to death? These frogs and toads produce high concentration of glucose, that acts like antifreeze. The glucose surrounds the vital organs preventing the cells form freezing and bursting. Their skin cells do from ice crystals, but they manage to survive. As winter wears on the temperature drop partially freezing these amphibians. It’s heart stops beating and it stops breathing, yet it is not dead. When the weather warms and ice melts, the frogs and toads begin to thaw. The thaw causes their heart to begin pumping and lungs to take in air again.
Aquatic frogs partially bury themselves in mud of the ponds and creeks. If they completely bury themselves, they will suffocate. Amphibians are able to breathe through their skin. The circulating water allows them to exchange oxygen during brumation. As long as the pond does not freeze solid they will survive.
Some aquatic turtles go to bottom of the water and settle into mud. In cold temperatures, their heart is barely beating and respiration is very slow. Lactic acid builds up in their body, but they use their shell to neutralize this waste. Their shell is made up calcium carbonate which chemically reacts with the acid. Some aquatic turtles retain their sensitivity to light to help alert them to warming temperatures.
Amphibians and reptiles use brumation as a method of surviving the winter so they can thrive through in the warmer months. As the spring approaches look for signs of frogs and turtles waking up from winter’s slumber. Next time, you spot these cold blooded critters take a moment to consider their survival during a long winter‘s nap.