Michelle Kelly and Eric Swanson | For Savannah Morning News
Published: Monday, January 11, 2021 at 2:46pm EST | Updated: Monday, January 11, 2021 at 5:00pm EST
Human ingenuity has made surviving winter’s biting chill so much more tolerable since industrialization. Our inventive brains have come up with a myriad of ways to warm our inside spaces. Our winter fat storage is not as necessary as it was for so many thousands of years when we lived more primitively. Many animals rely on that winter fat, stored from days of gathering and feasting, to survive the coldest nights. Our animals at Oatland Island Wildlife Center are given balanced diets, which along with their body coverings, sleeping habits and morphology, help them regulate their body temperature.
Fat and feathers make fantastic insulation for birds. You can check a bird’s fat storage by looking under their wings. Oatland’s birds have consistent food and therefore a good fat reserve. With a little fluffing up of their feathers and trapping warm air next to their bodies, they can maintain their normal, high internal body temperature that runs in excess of 104°F. Their biological mechanics, in addition to a little pine straw in the raptors’ nest boxes, makes for a cozy winter night. Pine is used in lieu of straw and other natural materials because it is more resistant to mold, which can cause respiratory problems in birds of prey.
Our larger mammals like wolves, bison, and deer grow thicker hair in winter as well as rely on their mass to thermal regulate. Size matters with heat retention. Minimizing the surface area to volume ratio reduces the amount of heat you lose out of your body. Said another way, the larger your volume, the smaller your surface area and the greater the heat retention. This is known as Bergmann’s rule. Ever wonder why polar bears are the largest bears? Their mighty size translates to a smaller surface area compared to a larger volume giving them the adaptation of retaining heat to withstand arctic winters.
In the barnyard, domesticated rabbits require more attention than their wild counterparts. Our rabbits can’t burrow in their exhibit, so we bring them inside when nights drop below 45°F. Burrowing animals. which include our foxes, tortoises and armadillos, take advantage of the earth’s insulation that provides a warm spot to hide away from cold temperatures. Wolves and alligators will also make dens to stay out of the cold air.
Our Georgia farm animals are provided shelter from cold in their cozy barn stalls. Donkeys originated in warm latitudes and tolerate the heat better than the cold, so we give our donkey Soldier Joe an insulated jacket. Our Ossabaw pigs Fernando and Ramon are provided insulation such as straw in their wooden houses (we haven’t upgraded to brick houses yet, sorry two little pigs). Domino the duck and Rosy the goose, our waterfowl, are thermally insulated with down and waterproof contour feathers.
Cold blooded animals including reptiles and amphibians shelter in water or muddy sediments during cold periods. Water transfers heat more slowly than air; therefore, lakes and ponds drop their temperatures more slowly than the ambient air. When it is cold for long periods these animals don’t hibernate. They go into a torpor state that is called brumation and can come out of it when the sun adequately warms the winter days.
Humans have the ability to manipulate the environment which allows them to inhabit some of the coldest regions on the globe. We have moved inside, so seeing animals outside in the cold often brings up feelings of sadness. We have to remember that our native animals, such as the animals cared for at Oatland Island Wildlife Center, have adapted to this climate in all its extremes. As long as they receive adequate food and shelter, they can survive the coldest nights. How about you?