A muskox is a large, shaggy mammal that lives in the Arctic regions of North America and Greenland. Despite its name and appearance, the muskox isn't actually an ox or closely related to cattle. It's more like a very stocky, heavily built goat covered in an incredibly thick coat of fur.

These remarkable animals survive in some of Earth's coldest places, where winter temperatures can drop to 40 degrees below zero. Their long, dark fur hangs almost to the ground like a skirt, and underneath lies a layer of soft wool called qiviut (pronounced “KIV-ee-ute”), which is eight times warmer than sheep's wool. This double-layered coat keeps them warm even in fierce Arctic blizzards.

When threatened by wolves or other predators, muskoxen form a defensive circle with their horns facing outward, protecting their young in the center. It's like a fortress of horns and fur. Adult males can weigh up to 900 pounds and stand about five feet tall at the shoulder.