Definition
Class Mammalia is a group of warm-blooded vertebrates characterized by fur or hair, mammary glands (for producing milk to feed their young), and three middle ear bones ð. Think of it as nature's VIP club for animals with these special features. Mammals give birth to live young (except for monotremes like the platypus), and range in size from tiny shrews to giant whales ðģ. They live in diverse habitats, from deserts to oceans. The key here is that milk production allows mothers to nourish their young.