By Laura & Hal Mahan
Think about all the things we do to get ready for cold weather. Make sure the storm windows are in. Bring in some fire wood. Check the furnace. Put flannel sheets on the bed. Get out the heavy wool sweaters. Stock up the pantry in case the power goes out. Maybe we even escape the cold by moving temporarily to warmer climes.
Now think about how animals and plants have strategies to accomplish the same thing. We wonder about the once abundant insects of summer. Where do they go? How do they withstand freezing temperatures and winter storms? What about the birds? The bears? The frogs and toads? It’s all about survival.
Migration is the most obvious strategy for escaping the colder months. Many birds fly south for the winter, some for very great distances. Other birds move around locally or regionally seeking food sources. Some of our mountain species migrate from high elevations to low elevations during the winter. In the Asheville area we usually see Dark-eyed Juncos only in the winter. They may have spent the summer nearby, but up high in our mountains. They are truly “snow birds!”
How do delicate, small creatures such as insects survive? Monarch butterflies fly all the way to the mountains of Mexico and then breed their way back next spring. Some insects find warm, sheltered spots to survive. We call it overwintering. Many insect species spend the winter in a dormant phase of their life cycle. Have you ever found a moth cocoon in the winter? They spin a cocoon of durable silk hung from a twig to protect the precious pupal stage of their life cycle, transforming into a beautiful moth as temperatures warm in a few months.
Hibernation is another adaptation for winter survival. Think of it as a long winter’s nap! Our black bears are a good example, although they can be active on warmer days. Most black bears are “denned up” by the end of December here. Yes, they do hibernate. Their breathing and heart rates slow down, and their body temperature is slightly lower. Females generally hibernate for a longer period than males. Cubs are born in January and are fed and cared for by mother bear until emerging from the den in early spring, ready to explore.
Cold-blooded animals like snakes, turtles and frogs are dependent on the sun’s warmth to avoid freezing, so survival depends on finding a freeze-free place. Burrowing under leaves and into the soil below frost line is critical. Some aquatic creatures burrow under mud. Some frogs can even endure being partially frozen, and then “come alive” when they thaw out! A high concentration of glucose in their blood prevents them from freezing solid.
Even plants have an overwintering strategy. Seeds are dormant, some needing cold treatment before they sprout in the spring. Root systems live below the frozen upper layers of soil. Trees drop leaves in the fall so that they do not lose as much water when less water is available. Buds survive the winter covered with durable scales that protect the new flowers and leaves within.
When you get your flannel sheets out of the closet, take a moment to reflect on the natural world and how life all around us here in our mountains prepares for winter!
Laura and Hal Mahan are owners of The Compleat Naturalist, located at 2 Brook Street in the Historic Biltmore Village. To learn more, visit CompleatNaturalist.com or call 828.274.5430.