Appalachia’s Smartest Winter Wildlife
By Daniel Manget
All it takes is one January walk in the Appalachian woods to make one ask the question, “how on earth can wildlife live out here all the time?” Most of us understand that there are methods such as extra layers of fat and fur, hibernation, ways to stash food, and other adaptations that make survival possible. However, those just seem like neat facts when you’re reading it on a computer in a nice warm house. After backpacking for a few days and nights in the frigid motionless winter woods, those adaptations don’t seem truly adequate for the job. After a looking a little deeper into some of the lesser known tactics, however, it seems that wildlife has come up with some really creative and wide-ranging ways to fight back against the big chill.
These are the organisms who have got it figured it out. Through millennia of numb toes (or paws), petrified mucous, long boring nights full of board games, and oh yeah starvation, these are the ones who said that enough is enough and figured out some genius methods of survival that would have made Darwin and the Eskimos proud. Some are a little more tough and honorable than others but who can judge a creature without central heat.
The Major Cop-Outs (AKA The Lucky Migrants)
One can’t blame the lucky flying birds to bail when winter becomes harsh. Just like human beings who are wealthy enough to own a house at the beach and in the mountains. I would think that having a flying heart rate of 500 beats per minute and wings that flap anywhere from 75 to 200 flaps per SECOND might make long migrations impossible for something that weighs a penny but it doesn’t stop the Ruby-Throated Hummingbird. They must really hate winter because they fly the 1000-ish miles from Appalachia to Southern Mexico/Central America to escape. To build up fat for the trip they must eat 1.5 to 3 times their body weight DAILY in nectar and insects in
order to double their body weight (the fastest metabolism in the animal kingdom). If they don’t eat enough they will simply not make the 500 mile nonstop flight across the Gulf Mexico and will likely die. They really hate winter.
The monarch butterfly migration is one that is well studied and celebrated for good reason, but scientists are just beginning to understand the miracle of dragonfly migration such as the Green Darner Dragonfly that frequents Appalachian bodies of water. Of the 331 species of dragonfly in North America, only 9 are long distance migrants. Like song birds, dragonflies store up fat, determine when it’s the right time to leave, follow predictable fly ways, and rest in safe places but, unlike birds they are taking a one way flight. They’ll only get to enjoy those hot rays for a few weeks before they die because, like monarchs, it is their offspring that will make the return journey in the spring and, like the monarchs, scientists have no idea why. One dragonfly from India actually strips the crown from the monarch as the longest migrating insect. The Globe Skimmer Dragonfly migrates over 11,000 miles!
The Minor Cop-Outs (AKA The lucky sleepers)
Most people don’t think about bees when thinking about hibernation but the queen bumblebee is the queen of hibernation. As the seasons turn cold, the newly chosen queen will say goodbye to the entire colony and find a bank to burrow into. She will remain there for 9 months while the entire rest of her colony freezes to death. Finally, she’ll emerge and begin her own colony by laying thousands of eggs and fertilizing them from the sperm she saved from the previous year. Pretty ruthless.
The Frozen Ones (AKA The seriously unlucky ones or lucky ones depending how you look at it)
If Darwin were to give an award to the animal with the most creative way to avoid winter, I think he would give it to the Wood Frog. Mainly because it doesn’t avoid winter at all. It is actually the only amphibian to live in THE ARCTIC CIRCLE! It does this simply by not fighting the cold but embracing it. There are several instances of animals being freeze tolerant but this little frog has taken it to a whole new level. When the temperature plummets, this frog can essentially become a frogsicle with two-thirds of its body freezing solid including most its brain. It stops all breathing and its heart stops beating for days or weeks on end. I know what you’re thinking, how can it survive this? And why on earth haven’t I used this science to freeze my family dog in a cryogenic chamber? Well it isn’t that simple. The Wood Frog has special proteins to ensure that its blood freezes first. When this happens the freezing blood sucks most of the moisture out of the frog’s cells which is replaced by a freeze tolerant glucose that protects the cells from freezing and becoming too dehydrated and collapsing (which is what happens when we freeze).
The only reptile that can rival the Wood Frog’s impressive freeze tolerance is that of the Eastern Painted Turtle which has a strikingly similar strategy of just giving up on staying warm and going ahead and freezing for the winter. It too stops breathing and the beating of its heart for an indeterminate amount of time.
The famous Wooly Bear Caterpillar, which is said to predict the winter weather based on the width of its middle band, lives as far north as the arctic circle and can survive in -60 degrees Celsius. The farther north it lives, the longer it takes to become a tiger moth which is why it has the longest life cycle out of any moth or butterfly, sometimes spanning 14 years! They don’t freeze solid but produce an antifreeze that keeps them going until spring.
The Tough Ones (AKA The ones that can’t bail)
While hibernation and migration are intelligent ways to avoid having to deal with the cold, many of our warm-blooded brethren don’t have such luxury. They’ve got a few physical tricks up their sleeve for dealing with it, such as lowering their body temperature at night, growing extra warm fur or feathers, creating food caches, and denning in large groups at night, but many just have to tough it out and work extra hard to maintain that extra body heat.
In general, the body type of all mammals, especially observable in humans, dictates how well one can retain that heat. The shorter and rounder ones that have less surface area have less contact with the outside air in which to lose heat while the thinner mammals with long extremities lose it faster and have a harder time staying warm.
If a group had to be chosen as the best adapted to actually live (not just sleep) in the frigid winter, it would have to be the birds. Everyone has probably seen a duck in a half frozen pond and wondered at how miserable they must be, especially with those thin exposed legs. Well one of their secrets is in those legs. The blood vessels in their legs are woven together tightly in a net-like pattern. When cold blood is returning from their feet it rubs up against the warm blood coming from their heart and neutralizes the temperature before entering the body and heart. Another tool is one that most birds have and is called a Preen gland which kicks in to keep the feathers oiled up and waterproof so that they don’t freeze.
The Chickadees are another notorious little tough guy for enduring the cold. Built like a little snowball, these stout critters can lower their body temperature dramatically at night and literally shiver their way through to stay warm and losing 10% of their body weight each night to do so. Poor little guy.
Ruffed Grouse are also champion survivalists both physically and behaviorally. Each fall the Grouse basically grows a snow shoe for winter, small nub-like projections off the side of the foot called pectinations, which also gives it gripping abilities and then fall off every spring. They are also expert tunnelers giving them access to foraging areas without exposing themselves to birds of prey.
Good luck wildlife. Spring is hopefully coming soon. Humans, enjoy your heat.