An animal that is both warm-blooded and lays eggs is called a monotreme. Monotremes are a unique group of mammals, with the platypus and echidnas (or spiny anteaters) being the only living examples. They are distinct from other mammals because, unlike most, they reproduce by laying eggs rather than giving birth to live young. Monotremes are warm-blooded, and their evolutionary traits represent an important link between reptiles and mammals. Their egg-laying behavior, combined with mammal characteristics like milk production for feeding their offspring, showcases the diversity and complexity of mammalian evolution.