Park naturalist Kurt Nelson photographed this ermine with the squirrel it hunted in Tettegouche State Park.
The weather forecast warns of temperatures plunging to minus 20 degrees Fahrenheit this weekend, far colder than what Viking fans endured one week ago in the Seattle game.
How do wildlife manage in the bitter cold? Surprisingly well, we discovered by asking the right people. Kelsey Olson, naturalist with Sibley State Park, Kory Klebe, environmental education leader at the Prairie Woods Environmental Learning Center, Curt Vacek, area wildlife manager with the Minnesota Department of Natural Resources, and John Loegering, certified wildlife biologist and wildlife extension specialist with the University of Minnesota, are among those who offered their observations on how wildlife do it.
For starters, the hardiest of the wildlife are like the true Viking fans at the game. They bundle up. White-tailed deer have already donned their dark-colored, winter coats. What’s most remarkable about their winter coat is that the fur consists of hollow hair, rather than the solid hair of summer. “Like a big, fluffy coat,’’ said Olson of the insulating value the hollow hairs provide.
Layers help too. Underneath the hollow hair are fine hairs that the deer can stand and fluff.
The coats are so efficient at trapping air and consequently body heat, it’s not unusual to see white-tailed deer with snow on their backs. There’s not enough heat escaping to melt it.
Park naturalist Kelsey Olson caught this image of an otter, one of two that were using holes in the ice to find food under the ice of a small wetland in Sibley State Park in December.
Beaver and muskrats also grow guard or hollow hair for winter, and take advantage of its insulating qualities, noted Klebe.
Thanks to weather forecasts, Viking fans had plenty of warning about the cold that was coming and how to prepare for it.
Wildlife benefit from advance warning too, according to Klebe. Most species of wildlife are sensitive to changes in barometric pressure, and consequently can anticipate the weather changes coming. The old saying about “bees never get caught out in the rain’’ has truth to it, he said.
When cold weather is approaching, animals such as squirrels will get more active and gather more of their stored cache in preparation for the cold. During the worst of it, they can huddle in their nests.
Other members of the squirrel family make inactivity their strategy all winter long. Olson pointed out that two cousins in the squirrel family tree, thirteen-lined squirrels and groundhogs, are true hibernators. Groundhogs (aka woodchucks) slow their breathing to one breath every six minutes. The heart rate drops from 75 per minute in the active season to four beats per minute.
A thirteen-lined squirrel rolls itself into a tight, sleepy ball in its hibernation chamber and remains inactive until warm weather arrives. Thirteen-lined squirrels will burn up fat reserves during hibernation, but do not lose any muscle mass. When spring comes, they are as fresh and ready to get into action as are the Viking reserves waiting on heated benches for the coach’s call to get in the game.
Fans who may have thinned their blood with alcohol at the Viking game only increased their susceptibility to the cold, but there are wildlife species who do use blood chemistry to their advantage. Wood frogs have an anti-freeze like blood that allows them to freeze overwinter and then thaw in the spring, reported Professor Loegering. They find refuge in the leaf litter above the soil, he noted.
Many insects survive freezing. Some do it the easy way with aquatic larvae that overwinter at the bottom of lakes and rivers, where the temperature never gets below 39 degrees, he explained.
Park naturalist Kelsey Olson took this photo of an eagle circling the small wetland in Sibley State Park where two otters were hauling the food they caught on to the ice. The eagle made a few dives hoping to nab some of the food.
There are some wildlife species that embrace the challenge of cold weather, perhaps none better than the black capped chickadee. Olson calls them the ‘’rock star’’ of winter. Although they weigh no more than a paper clip, they are active through the winter, singing loudly and when needed, collecting the seeds they’ve stashed and hidden away for cold, snow covered days.
When night arrives, these fast-paced birds do an about face. They go into a regulated hypothermia, said Olson. Their body temperatures drops by 12 to 15 degrees and they slow way down. It saves 25 percent of the energy they would otherwise need for those bitter cold nights.
We all know about the snowshoe hares and their ability to don white-colored fur to become invisible to predators. Weasels know this trick too, turning from brown to snow white as the days shorten and winter approaches.
Many smaller species of wildlife rely on mother nature and a coating of snow to insulate them and help them hide from predators during the winter. Mice burrow deep into the snow and move about in snow tunnels, said Klebe.
Minnesota’s three species of voles- the Southern Red-backed vole, Meadow vole and prairie vole- become subnivean. They live in tunnels under the snow, said Olson. They feed on fungi, roots and shoots.
If there is a deep snowpack, voles are well protected from the owls that prey on them.
One of Minnesota’s best wildlife success stories is the re-introduction of wild turkeys. Vacek participated in some of the early research at the Madelia research station that proved these hardy birds are indeed Minnesota natives.
Researchers wondered whether the cold would limit their range in the state. Researchers had a freezer capable of chilling down to minus 65 degrees Fahrenheit. Turkeys would be placed in the freezer overnight. Their metabolism would slow way down, but they always came back to life when researchers pulled them out in the morning. As they warmed, they’d shake the frost off and start moving about “like nothing ever happened,’’ said Vacek. It was obvious that cold would not be a limiting factor in their range.
Our winter scenery may seem quiet and inactive, but many species of wildlife remain very active through the worst of the cold. Park naturalist Kelsey Olson took this photograph earlier this winter in Sibley State Park.
Even some of the area’s non-native species, such as the ring-necked pheasant, are able to cope with the cold of winter. Winter pheasant mortality is usually the result of suffocation from snow and ice during harsh, late winter storms or snowpacks that make it difficult for them to reach their food sources. If there’s food, they can endure numbing cold.
So far, this winter has been a relatively mild one from the perspective of most wildlife. There is not much of snowpack to keep them from food, and we experienced a very long and warmer than average autumn, noted Jeff Miller, assistant wildlife manager with the Minnesota Department of Natural Resources in New London.
Miller said wildlife populations in the region entered this winter in good shape, thanks to a stretch of favorable weather that dates through last winter. While every winter’s blast of bitter cold will bring calls to the wildlife office inquiring whether to set out feed for pheasants, his advice at this point is “no.’’ It can do more harm than good, and once started, feeding must be maintained through the entire winter.
Unlike football games, there is no knowing when it’s over. There could be a long winter still ahead.
Many insects survive freezing the easy way with aquatic larvae that overwinter at the bottom of lakes and rivers, where temperatures never get below 39 degrees F.