Even though the climate of the Frigid Zone is harsh and inhospitable to most forms of life, many organisms thrive there, having evolved the mechanisms necessary to survive under such conditions over millions of years. The oceans of the Frigid Zone teem with life; by contrast, plants and animals sparsely populate the terrestrial habitats of the Frigid Zone. Many organisms that live there use unusual adaptations to survive.
The single most important factor that living organisms must cope with in the Frigid Zone is the low average temperatures. Most of the large animals that have evolved to live in these areas have dense fur and high amounts of body fat or blubber, which helps insulate them against the cold. Additionally, food is hard to come by in the Frigid Zone, as the plant life is sparse. Accordingly, many of the land animals consume food from the ocean. Others, such as reindeer, have evolved to eat the hardy plant-like lichens that are abundant in these areas.
Aristotle coined the term Frigid Zone along with the terms Temperate Zone and the Torrid Zone. He held that life could not exist in such inhospitable and permanently frozen places, but his assumption was not correct, according to About.com.