Dutiful mothers, female polar bears usually give birth to twin cubs, which stay with her for more than two years until they can hunt and survive on their own.

A sleeping polar bear looks adorable, but beware! With no natural enemies, polar bears are at the top of the Arctic food chain. They are fearless, and will readily attack humans.

In winter, female polar bears give birth to two cubs in an igloo-like den, which insulates the mother and babies against the brutal winds and frigid Arctic temperatures outside.

With their slightly webbed paws and powerful muscles, polar bears are excellent swimmers. Their favorite meal is seals, but they will eat anything they can catch, even scavenging through garbage in areas where their habitat overlaps with humans.

Polar bear paws have thick fur and sharp claws. The fur gives them better traction on ice, while the claws are excellent weapons for hunting.

A fine dusting of snow is blown into the air as two fearsome polar bears wrestle in this spectacular photograph.

Polar bear cubs Ganuk play together at the St-Felicien Wildlife Zoo in St-Felicien, Quebec, celebrating their first birthday.