Mammals:
* Polar bears: Known for their thick layer of fur and a thick layer of blubber (fat) to survive freezing Arctic temperatures.
* Arctic foxes: Have dense, white fur in winter, turning gray or brown in summer, for camouflage and insulation.
* Reindeer: Have two layers of fur, one dense and woolly, the other longer and coarse, providing excellent insulation in cold tundra environments.
* Walruses: Have a thick layer of blubber for insulation and buoyancy in the icy waters of the Arctic.
* Seals: Have blubber for insulation and a layer of fur for extra protection.
* Musk oxen: Have a double coat of fur, with a thick undercoat and long, coarse outer hairs, providing exceptional warmth in the Arctic tundra.
* Mountain goats: Have a thick coat of fur for insulation in high-altitude environments.
* Bears (except for black bears): Most bears have thick layers of fat and fur for surviving cold winters.
Birds:
* Penguins: Have a dense layer of feathers for insulation and waterproof protection in icy environments.
* Ptarmigans: Have white feathers in winter for camouflage and a thick undercoat for warmth, changing to brown in summer.
* Snowy owls: Have dense, white plumage for camouflage and insulation in the Arctic.
* Ducks: Have a thick layer of down feathers for insulation and water-repellent feathers for staying dry.
Other Animals:
* Arctic fish: Some species have antifreeze proteins in their blood to prevent freezing in the Arctic.
It's important to note that this is not an exhaustive list, and many other animals possess adaptations for surviving cold climates, including fur and fat.