1. Arctic Ground Squirrel: This North American rodent enters a state of deep torpor during hibernation. Its body temperature drops close to freezing, and its heart rate and breathing slow down dramatically, allowing it to survive in sub-zero temperatures.
2. Siberian Husky: A dog breed initially bred for sledding in extremely cold conditions, Siberian Huskies have thick, double-layered coats that provide excellent insulation. They can withstand temperatures as low as -50 degrees Fahrenheit (-46 degrees Celsius).
3. Emperor Penguin: Found in Antarctica, the harshest continent on Earth, Emperor Penguins endure freezing temperatures while breeding. They huddle together in large groups, alternating between the center and the periphery to share body heat and protect their eggs.
4. Arctic Fox: Another Arctic species, the Arctic Fox has dense, white fur that insulates it against the extreme cold. It can survive in temperatures down to -58 degrees Fahrenheit (-50 degrees Celsius).
5. Polar Bear: As iconic Arctic marine mammals, Polar Bears are well-adapted to withstand frigid conditions. They possess a layer of thick, water-resistant fur and a subcutaneous fat layer that provides insulation. Polar Bears can endure temperatures as low as -40 degrees Fahrenheit (-40 degrees Celsius).
These are just a few examples of mammals that have evolved remarkable strategies to survive in exceptionally cold environments. It is important to note that individual animals within the same species may have different tolerance levels, and some rely on specific behaviors, such as seeking shelter, huddling, or storing food, to cope with extreme temperatures.