Polar bear fur is transparent, it just looks like it's white because it reflects sunlight.
The city of Churchill in Manitoba, Canda, uses helicopters and armed volunteers to surround the city and defend it from Polar bears during Halloween trick or treat night. Noise markers, rubber bullets and even bear traps are used.
The arctic ground squirrel hibernates at 26 degrees Fahrenheit (-3 Celsius), the lowest temperature ever recorded in any live mammal. Despite the frigid temperature, it's blood continues to flow without freezing.