Mammals are warm-blooded animals that nourish their young with milk. They come in a wide variety of forms, including people, apes, dogs, mice, elephants and pandas. Mammals have developed different adaptations to live in diverse environments, such as fur and fat to survive cold climates or sweating and panting to release heat in warm places. Mammals also have different diets and include herbivores, carnivores, omnivores and insectivores. They vary greatly in size, from the smallest pygmy shrew and bumblebee bat to the largest blue whale.