How Do Iowa Animals Survive the Cold?
By Naturalist Raina Genaw
While extreme temperatures pose a pretty big threat to most wildlife, having cold weather is also just a natural part of winter! Animals have found many ways to survive in even the coldest conditions, and they have found ingenious ways to make use of it! Many Iowa animals rely on winter's low temperatures to trigger hibernation and brumation each winter. Snow provides extra camouflage for animals like the short-tailed weasel that turn white in winter, and snow pack provides a safe area for small rodents to tunnel and venture from their underground burrows in search food during the winter with little chance of being spotted. Snow can also act like a blanket for hibernating animals like caterpillars and snakes, protecting them from sudden temperature drops and blizzards.
While snow and cold provide general benefits to wildlife as mentioned above, animals still tend to prefer to take shelter from the bitter cold, and their shelter can take many forms. Pheasants take shelter in tall prairie grasses, chipmunks stay hidden underground, squirrels stay in leaf nests or tree dens, and small birds shelter in roosting boxes, attics, hollow trees, or any other warm space they can fit into. Most animals also invite others of the same species to share their winter shelter, which helps to provide more body heat and raise the temperature inside the shelter. Going outside less leads to being less active, which means animals save their energy, need less food, and have less chance of freezing from outdoor temperatures.
Many animals built up a decent fat store in warmer months to prepare for winter, which acts like a coat to keep them warm. When animals leave their homes in winter, it's usually to find food during the early morning or late evening. Having high fat stores means that animals are less affected by food scarcity in winter and therefore don't need to eat as much to avoid starvation.
When temperatures start to drop, wild animals are already equipped with super warm winter coverings. Thick fur coats and feathers help keep animals from freezing, though frostbite and hypothermia are still possible. Possums are especially prone to frostbite during cold snaps because they have no fur on their ears or tails; while they may suffer damage to those parts of their body, they won't necessarily die from it.
You may notice small songbirds becoming scarce after a freeze, which can indicate that they are either staying warm in their roosts or have succumbed to the freezing temperatures. Small birds are particularly at-risk from cold snaps because they aren't able to store as much fat in their bodies as other animals due to their need to stay light for flight. This means that they need to search for food more often, even in bitter cold. Luckily, they aren't defenseless against the cold! Birds have warm, fluffy feathers that keep them warm (like a down-feather blanket) and have a special way to heat up blood that travels to their featherless legs to avoid freezing. Birds also have excellent sense of direction in winter that helps them remember where they have stored food, just like squirrels digging for acorns! That being said, filling your bird feeders with high-fat foods like peanuts or sunflower seeds during a cold snap is a great idea to make searching for food quicker and easier for our feathered friends--just make sure your bird feeder is near trees, bushes, or tall grass that can be used as cover to conceal small birds from hungry predators like cats and hawks.
From a conservation standpoint, having a big freeze like this isn't all bad, either. Interestingly enough, while extreme cold can indeed harm native wildlife, big freezes like this can also help kill off invasive species like Emerald Ash Borers. Emerald Ash Borers, known for causing extensive damage to Iowa's forests, survive as worm-like larva in the winter and later emerge as beetles when temperatures rise. While Emerald Ash Borer larvae are no stranger to cold winters, they cannot survive fully freezing and quickly begin to die off as temperatures drop into negative numbers.
Maybe winter isn't as bad as we think, after all! Iowa's animals have found many ingenious ways to survive- and sometimes thrive- in winter, and winter's chilly arrival provides many unexpected benefits to our ecosystem.