CHICAGO – The brutal cold expected to descend upon Chicago this week could be deadly for many animals that live outdoors, but experts say it’s likely that the populations of everything from stray cats to stink bugs will escape lasting damage.

That’s because animals have strategies to endure all manner of harsh weather, even cold that might break Chicago’s record low of 27 degrees below zero. They bore into trees, burrow beneath the frost line or find refuge in abandoned houses. And even if they don’t make it, plenty of others will, and they’ll rapidly restore their numbers once the weather improves.

“These things have been here since the glacial times,” said Michael Jeffords, a retired entomologist with the Illinois Natural History Survey. “Their genetic memory is like, ‘Ah yeah, this will pass.’ If we had (extreme cold) for weeks and weeks, it would have an impact, but I think they’ll be OK.”

Feral cats are among the critters endangered by the cold. There are an estimated 200,000 in Chicago alone, and some are cared for by “colony caretakers” trained by organizations like PAWS Chicago.

Laurie Maxwell, PAWS’ director of community outreach, said cats are exceptionally resilient, finding shelter under cars or dumpsters and inside vacant buildings. During extreme cold, they save energy by hunkering down and remaining still.

Even so, people who care for strays can increase the animals’ chances of survival by making sure they have food and water – heated water bowls prevent freezing, as do bowls that are exceptionally deep – along with rudimentary shelter. Maxwell said people can build a cheap and simple cat refuge by cutting a small hole in a plastic storage tub, lining it with foam insulation and layering the bottom with straw.

Another option, for those who can do it, is to let feral cats wait out the worst of the cold in a spare room or even a screened porch.

“With the wind chills we’re facing, even if it’s (minus) 40 degrees on your porch, if they’re protected from the wind, that can save their lives,” Maxwell said.
Other species don’t get that sort of consideration, but they’re equally adept at enduring unforgiving conditions.

Lawrence Heaney, the Negaunee curator of mammals at the Field Museum, said hibernating animals like chipmunks have adequate body fat and insulated hiding places that allow them to survive the cold. But animals like deer, squirrels and coyotes that stay active during the winter could be in trouble.

Monday’s relative warmth, soon to be followed by a deep freeze, means their shelters could end up coated in ice, he said.

“The places where they hide under the brush, it’s all getting wet, and now it’s going to drop down to close to 20 below,” he said. “That combination is really, really hard on them.”

But even if there is a significant die-off in some species, he said, the populations will quickly grow once winter passes. Fewer deer, for example, means more food for those that remain, giving their babies a better chance at survival.

“Pretty much every species produces more offspring than is needed to replace their parents,” he said. “Even with bad weather, disease or predation, they fill in the space really quickly.”

The same is true, regrettably, with insect pests.

Jeffords said while the stink bugs that emerge during mild winters could be “knocked back” by extreme cold, he would expect their numbers to rebound swiftly. Mosquitoes, meanwhile, protect themselves by spending the winter in urban sewers and steam tunnels.

Insects like the emerald ash borer that gnaw their way into trees are even harder to kill. Phil Nixon, a retired entomologist with the University of Illinois Extension, said they won’t die in substantial numbers until the temperature drops to 30 degrees below zero.

He noted, though, that one insect can be endangered by extraordinary, long-lasting cold.

“Three consecutive days with highs no higher than 20 degrees below zero will kill most overwintering gypsy moth eggs,” he said. “The Chicago area came close to that in the mid-1980s, and (the) gypsy moth was severely impacted. (A single) overnight low of minus 21 will have little effect on them.”

On the other end of the animal kingdom, a few species might actually enjoy record-setting low temperatures.

Both the Lincoln Park Zoo and the Brookfield Zoo say they will allow their polar bears to remain outside during the worst of the chill (they’ll still have access to heated spaces indoors). The animals are native to climes that experience cold well below zero, so the week’s freeze won’t be anything they can’t handle, said Mike Murray, curator of mammals at the Lincoln Park Zoo.

“It really doesn’t get too cold here in Chicago,” he said. “Even with the arctic blast coming up, they’ll be outside.”

Brookfield Zoo has other hardy species like snow leopards and bison that will have the chance to brave the cold, too, but other animals, such as kangaroos and wallabies, will be barred from going outside, said Bill Zeigler, senior vice president of animal programs for the Chicago Zoological Society.

“Even though these animals may have fur on them, their toes can experience frostbite,” he said. “We’re just not going to be taking that chance.”

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