Photo Caption: It’s hard for humans to comprehend, but native wildlife in good condition have the instincts and skills needed to survive the occasional blasts of winter we receive in northern Illinois. (Photo credit: Valerie Blaine)
Good Natured: Animals in Extreme Cold
Special Column — February 5, 2019
This departure from the regular column is in response to the recent record-setting cold the National Weather Service described as “life threatening.” Our resident expert, Good Natured writer Pam Otto, answers some questions about the super-cold.
Q: How many deer will die in our area?
A: Can’t put a firm number on this but can answer with another question.How many deer were sick, injured or elderly before the cold hit? Those conditions will put any animal at a disadvantage for surviving. Is it a death sentence? Depends on the severity of the infirmity and the duration of the cold spell. But I guess another and perhaps more optimistic way of looking at things is that healthy deer should be fine over the next few days. Their preparation for winter began months ago. Back in, say, September, they started shedding their gorgeous reddish summer coats and replacing them with the drabber brown-gray that is their winter pelage. Besides being a different color this fur also has quite a different texture. It’s longer and thicker and each individual hair is actually hollow, a neat adaptation that allows the air inside to act as an insulator. White-tailed deer also have an advantage in that their metabolism slows in cold weather, which means their calorie intake can be less. This adaptation combined with the fact that they can eat many different kinds of bark, twigs and shoots means that they can browse pretty effectively even when the “easy” food like corn is buried under snow. You’ll also notice, most bucks have shed their antlers by now.No use lugging around something heavy and impractical now that mating season is over. One other thing: deer bed down a lot more in winter and are able to use the snow as an effective wind block. So will deer die during this cold snap? Some, yes. But I’m pretty sure it won’t be the widespread carnage you might expect.
Q: Ditto for coyote, fox, raccoons, other mammals?
A: Fitness definitely plays a role in survival for these guys too but being omnivores (as opposed to deer, which are primarily plant eaters) their behaviors are going to have to be modified considerably during the cold. Coyotes and foxes can take a short break from feeding, provided their winter coats came in well and they have fed well up til now, but I don’t think their metabolism slows all that much. They’ll do their best to find shelter and stay out of the wind, and probably get pretty hungry because there’s not going to be much prey out and about. Those big fluffy tails are used like a blanket to cover the nose/face; that’s why individuals with mange are in big trouble right now.
Suburbia’s big three, raccoons, opossums and skunks, being smaller, are right now holed up in places in a variety of natural and man-made shelters. Hollow trees are popular with raccoons and opossums but so are the spaces under decks and sheds as well as up in garages and attics.
Skunks will almost always be in groups in underground spaces, typically a burrow dug by something else, and of the three species are the least active in winter. Again, advance prep is key to all three species’ survival. Thicker fur and layers of fat will help sustain them when they can’t go out and feed. They can also enter a state of torpor, where their body temperature drops and they don’t move much at all. Of those three, opossums have it the worst. With their naked tails and ears, they’re poorly adapted to this climate. Even the best prepared of them might not survive a prolonged cold snap. But they won’t all die. And, come spring, their numbers will rebound thanks to their high reproductive rate.
Squirrels survival strategies include the above-mentioned added fat, but also the food they cached before going into winter.Sure it will be harder to excavate through the snow but they will still remember where it is. And for the neighborhood squirrels there’s also bird feeders. Shelter is also important for squirrels and their number one choice would be a tree cavity. There they can buddy up inside and share body heat. But those big leafy nests can be surprisingly well insulated too. There are layers of air between the leaves and the whole wad is bound together with twigs. Is it as snug as a woodsy cabin with a roaring fire? No, but it does the trick most of the time.
Then there are rabbits. Like deer, they are herbivorous and right now are chewing on lots of different types of plant material. One other thing, they need to eat their poop in order to maintain their gut flora. So when they’re not chewing on plant material, they may be munching on poo. Rabbits don’t dig burrows and they can’t climb up into tree cavities but they are adept at finding shelter under snow-covered shrubs, brush piles and even flopped-over tall grasses. Snow is actually a pretty good insulator and wind block, and the deeper it is the warmer it is down near the ground surface. Not warm-warm, but something like 32F, which is like 80F warmer than what our wind chill was today.
Q: Could cold of this extreme actually wipe out a population?
A: I don’t think so but it depends on how you define population. If there was a group of, say, skunks that opted for a burrow somewhere that wasn’t deep enough, they could freeze to death. Or they could all succumb to respiratory infections, which is pretty common and easy to share in confined spaces. But would the entire population of skunks in the TriCities get wiped out? Nope. I know a lot of people will be bummed to hear that, but I’m a fan of skunks and their pest-killing talents so I for one–yeah, maybe the only one–will be cheering for them to make good choices and burrow deeply.
Q: Any other living creatures likely to die from this? If so, any numbers?
A: We humans are really most poorly adapted of all the local creatures. Our naked skin requires layers of clothing for protection and if we’re not kept at hothouse temperatures we get sniffly and suffer all sorts of other ailments. By association, animals we’ve brought with us to this climate can also have a hard time. Dogs and cats have lost a lot of the behaviors and adaptations their wild cousins have and hence can have just as tough a time as we do. But I’m sure there are those huskies and malamutes out there that are reveling in the cold.
All birds have pretty high energy requirements in winter because they can’t really store up a lot of fat or they wouldn’t be able to fly. So they need to rely on the insulating qualities of their feathers as well as the snow that piles up on brush piles, shrubs and evergreens. They shiver a lot to stay warm and some species will pile up together in tree cavities as well as birdhouses and other manmade structures. Birds of prey can really have a hard go of it as they tend to be more solitary and less snuggly than songbirds. Waterfowl will head for open water because it will be way warmer than the air temps.
We could go on and on about reptiles and amphibians (some amazing adaptations here, including a few frog species that actually can freeze solid, thaw in spring and be fine), insects and spiders but I’ll just mention a few critters that may be on people’s minds. “At least the cold will kill off the mosquitoes,” folks tend to say. Well, not so much. Some seek shelter indoors in winter but most species overwinter in the egg stage, in water. Come spring when the water warms up the eggs will hatch and the skeets will be back. Then there are the stinging things. Wasp queens, like those of yellow jackets and bald-faced hornets, are hunkered down in leaf litter and downed logs. If they didn’t choose their overwintering spots wisely some may die but most usually survive cold snaps like this and will start new colonies in spring. Finally , there’s the ticks. They’re out there and are amazingly resilient. When warm weather returns they will be back too.
Pam Otto is the manager of nature programs and interpretive services at the Hickory Knolls Discovery Center, a facility of the St. Charles Park District. She can be reached at 630-513-4346 or firstname.lastname@example.org.