The Arctic and Antarctic are areas on Earth with extremely low temperatures, so animals have developed special survival strategies and adaptations to prevent heat loss. Adaptations include morphological and physiological adaptations. Morphological adaptations are specific feathers in birds, hair, fur and a thick layer of fat in mammals. Physiological adaptations are antifreeze proteins that prevent body fluids from freezing. Terrestrial mammals live in the Arctic; polar bear, arctic fox, arctic wolf, reindeer (reindeer), musk oxen and arctic hare and lemming. Food chains are very short and consist of only three members. In the sea around the Arctic, there are species of seals and whales, and some species of cod are represented as fish. Unlike the Arctic, there are no land mammals in Antarctica. The Antarctic land is inhabited by emperor penguins, and the sea is inhabited by various species of marine mammals such as the Antarctic blue whale, the orca whale from the dolphin family, and seals (sea leopard, crustacean seal, Weddell seal). Of the fish, species from the cold cod family are common. The melting of the ice sheet due to global warming significantly affects the survival of animals that are adapted to life on ice. The consequences can be the extinction of certain species and the reduction of biodiversity.