Monotremes

Monotremes are a group of egg-laying mammals, which include the platypus and echidnas. They are the only mammals that produce milk through mammary glands located on their skin rather than through nipples. Monotremes are important because they are the oldest group of mammals and are unique among mammals for their reproductive and behavioral characteristics. They are also a valuable resource for the study of evolutionary biology, as they represent the link between reptiles and mammals. Monotremes inhabit many parts of the world and have been used for conservation and educational purposes.