In the wild, polar bears thrive in some of the world’s coldest places. Hell, they don’t mind swimming among ice flows around the North Pole. But those who live in cities well below the arctic circle just don’t have the same constitutions. That’s why Anana, the polar bear at Chicago’s Lincoln Park Zoo, is spending this polar vortex indoors, away from the sub-zero temperatures. Polar bears in the wild put on a layer of blubber, zoo spokeswoman Sharon Dewar told DNAinfo, but Anana didn’t grow one thanks to Chicago’s warmer climate. The Bronx Zoo’s Tundra, the city’s lone polar bear (RIP Gus), apparently also forgoes that heavy-duty insulated coat. But with temperatures expected in the single digits (negative teens with wind chill), even Tundra might want to spend Tuesday huddled indoors.