polar bear walking across snow

It’s International Polar Bear Day and what better way to celebrate these brawny yet somehow still adorable bears — I mean, have you seen our photos of Siku? — than to share some I-never-knew-that facts about the Arctic-roaming creatures.

Fact 1: Polar bears and penguins do not live in the same place.

No way, you say. You’ve seen them depicted together a million times! But consider this: It was always a cartoon or an illustration, never a photograph, right? That’s because, in real life, the two species dwell at opposite ends of the earth: Polar bears live in the Arctic and penguins hang out in the Antarctic.

Study your ancient Greek for further proof: The word “Arctic” derives from the Greek word for bear, while Antarctic in Greek means “without bear.”

Fact 2: The polar bear is the largest land-dwelling carnivore.

Brown bears can be equally hefty when it comes to mass, but polar bears are much taller — they can reach heights of up to 10 feet.

Fact 3: Male polar bears are twice as big as females.

Males normally weigh between 775 and 1,200 pounds, while females pack on between 330 and 650 pounds. It’s not unusual for male mammals to be somewhat larger than females — but not that much bigger. The only other mammals that have such a big weight difference between the sexes: seals and sea lions.

Fact 4: Polar bears are so well insulated that they’re nearly invisible — even to infrared cameras.

Scientists realized this while trying to do aerial population surveys, because they found that the white bears were hard to make out against snow, so they tried heat-sensing infrared. But since so little heat escapes from their bodies through blubber and fur, the only features that showed up were their eyes and noses.

Fact 5: Although polar bears look white, the skin under their fur is actually black.

The hairs of the outer layer of the coat are hollow and lack pigment, so they appear white to our eyes because they scatter and reflect light, just like the snow that the bears tread on.

Fact 6: Male polar bears have longer hair on their forelegs.

Much like the mane of a lion, this feature is thought to be attractive to the polar bear ladies.

Fact 7: Polar bears are intrepid travelers.

Their home territory can range from 20,00 square miles — in places where food is abundant — to over 100,000 square miles, where prey is scarce. One female who was tracked by satellite roamed 3,000 miles from Alaska to Greenland to Canada and then back to Greenland — and she was walking the whole way!

Fact 8: Polar bears have an amazing sense of smell.

A hungry bear can pick up on a seal that’s over half a mile away — or in a den completely covered with snow. They can even sniff out a seal’s breathing hole in the ice — a polar bear’s favorite hunting spot — from a mile away.

Fact 9: Seals are the biggest part of a polar bear’s diet, but they can develop a taste for junk food.

We’re talking real junk: They’ve been known to eat Styrofoam, plastic, car batteries, ethylene glycol, hydraulic fluid and motor oil. For this reason, Churchill, Manitoba, has been trucking all of its trash out of town since 2006 after discovering that polar bears were using its dump as a buffet.

Fact 10: The indigenous peoples of the Arctic hunt the polar bear, but there’s one part you should never eat: the liver.

There’s so much vitamin A concentrated in a polar bear’s liver that it can make humans seriously ill, producing symptoms like headache, nausea, peeling skin and blurred vision.

Linda Lombardi is a former zookeeper, college professor and the author of Animals Behaving Badly, a new book that grew from her blog of the same name.