Whitetails are survival machines in winter; here’s how they do it

While the Upper Midwest has experienced some bouts of mild weather the past few weeks, it’s undeniable that winter is here. We’ve gone through a few blizzards, 40-mph winds, and temperatures that didn’t crack double digits for days at a time.

While we sit in our cozy houses and bundle up every time we head outdoors, Mother Nature is just out there doing her thing.

It’s hard to believe any critter can survive months of prolonged cold, snow, ice, and far more hours of darkness than daylight. Some opt out. For example, black bears, which have the right idea when it comes to dealing with winter. Others, such as whitetails, tend to do just fine during your average winter. They do this through unique adaptations.

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Yarding up

Before getting into their physiology, it’s important to understand that the deer itself needs a little winter help from habitat. When you get far enough north, deer yards are commonly known by both humans and four-legged predators.

Whitetails in the north country have to seek out geothermal cover that exists near browse and other food sources. This does a couple of things for them.

The first is that there is some security in numbers, even if those numbers also might attract more predators. The second is that geothermal cover, like a thick patch of conifers, not only protects them from the wind, but also attracts available sunlight to create a microhabitat that is more advantageous than the surrounding areas.

Of course, this is only the beginning.

Deer also need to dress up to make it through the worst that winter has to offer them.

Winter coats

If you’ve ever sat during a late-season cold snap and watched deer, you probably remember them looking a little puffed up. You’ve also probably gotten goosebumps more than a few times when you’ve been cold.

This isn’t just a random response to being chilly; it’s an evolutionary holdover from when we had a lot more hair on our bodies than we do now.

Deer do the same thing, which allows their hollow guard hairs and their finer, almost woolly close-to-the-skin hairs, to work together to create not only a barrier against the cold, but an insulating layer that further keeps them warm. Its effectiveness is evidenced by how deer can be bedded during a blizzard and be covered in snow that won’t melt on their backs while their bodies stay warm.

Living fuel tanks

Hunters looking to tag out on a buck any time from bow opener to the pre-rut would do well to focus on food sources. Deer think with their stomachs for about 11 months each year, and it’s only during the rut that they really turn their attention elsewhere. This tunnel vision when it comes to calories is understandable, given they need a lot of fuel to survive the winter.

Deer that have spent enough time gorging themselves at the browse buffet can enter winter in a way that will allow them to lose around 25% of their body weight during the slow slog to spring. This doesn’t take into account bucks and their general body condition after the rut, which has them depleted and in need of some bulking up.

This is most easily understood if you’re lucky enough to fill your tag before the late-season kicks in. Whether that’s on a doe or a buck, you’ll probably notice a layer of fat along their backs and their rumps, which can be a couple of inches thick. Boiled down to its simplest form, this is stored energy.

The deer that has decent fat reserves is one that can borrow from earlier times of food abundance once the temperatures plummet and a lot of the food that’s left is low-quality browse. While we take calorie-dense food for granted, deer don’t, and it’s truly a matter of survival for them to scrounge up a bunch of acorns and other quality food sources weeks or months before the first snowflake ever falls.