Animals have adaptations that allow them to live in particular climates due to natural selection and gene mutations. For example, polar bears have a thick layer of fat for insulation, and hairs that can transmit sunlight to the dark skin beneath which can maximize the heat they absorb. They have small ears that minimize heat loss to the environment and guard hairs to repel water. Their dense undercoat even covers their feet. In desert climates, water loss is minimized in the urine or feces, or through the skin which is usually waterproof. Heat can radiate out of larger ears as seen in certain rabbits, or by having longer appendages or small bodies. These are but a few examples of adaptations to climate.