Take a plunge into the wonderful world of these Arctic ambassadors… 1. Polar bears are the largest and longest species of bear. Males can measure up to 10 feet (3 meters) when standing on their hind legs. 2. Scientists believe that the polar bear evolved from a common brown bear ancestor about 200,000 years ago. 3. Even though they look white, a polar bear’s fur is made of clear, hollow tubes filled with air. 4. Polar bears clean themselves by rolling in the snow. 5. They also cool off by rolling in the snow or taking a dip in chilly waters. [caption id="attachment_113304" align="aligncenter" width="1200"] photo by Ion Moe[/caption] 6. A group of polar bears is sometimes called a pack or sleuth. 7. Unlike their brown and black counterparts, polar bears do not hibernate. 8. Polar bears are found in countries that ring the Arctic Circle—Canada, the US, Greenland, Russia, and Norway. 9. Polar bears have no natural enemies. 10. They can swim at speeds of up to 6 miles per hour (8 knots). In fact, their taxonomic name means “sea bear.” 11. Polar bears have been known to swim more than 60 miles (100 kilometers) without rest in search for food. Unfortunately, that distance is increasing due to climate change. 12. Their nose is so powerful it can smell a seal on the ice 20 miles (32 kilometers) away, sniff out a seal’s den that has been covered with snow, and even find a seal’s air hole up to 1 mile (1.6 kilometers) away. [caption id="attachment_113302" align="aligncenter" width="1600"] photo by Helene Hoffman[/caption] 13. When they aren’t hunting, polar bears are resting up to 20 hours a day. 14. Because their habitat vanishes for a few months every year, polar bears have evolved one of the longest fasting periods of any animal. 15. Polar bears typically kill and eat prey every four to five days. 16. A polar bear’s fat acts as a nutritional reserve and energy storage system when food can’t be found. It also increases their buoyancy when they swim. 17. They have built-in socks. Stiff fur on the sole of each foot keeps the polar bear from slipping on ice, and also muffles the sound of the bear’s approach when sneaking up on a meal. [caption id="attachment_113301" align="aligncenter" width="667"] photo By Helene Hoffman[/caption] 18. Except for females with cubs, polar bears are solitary. [caption id="attachment_113303" align="aligncenter" width="1000"] photo by Helene Hoffman[/caption] 19. Polar bear pregnancies are triggered by a female’s body condition and environmental factors, most often between September and November. [caption id="attachment_113312" align="aligncenter" width="1000"] photo by Helene Hoffman[/caption] 20. This process, known as delayed implantation, is an adaption that ensures polar bear cubs will be born to healthy mothers at a time when their chances for survival are greatest. [caption id="attachment_113309" align="aligncenter" width="1000"] photo by Helene Hoffman[/caption] 21. Polar bear cubs weigh a mere 1 pound (.45 kilograms) at birth. They are hairless and have their eyes closed, depending on their mother to keep them warm and fed.   Do you have any polar bear facts to add to this list? Share yours in the comments below.   Jenn Beening is the social media planner for San Diego Zoo Global. Read her previous post, 11 Animals That Feast Together.