Introducing Mammals!
Most of the animals we keep as pets, such as dogs, cats, and rabbits, and the animals we use for work, such as horses, are mammals. Humans are mammals too. Mammals belong to a group of animals called vertebrates , all of which have backbones. They are warm-blooded, which means they have a constant body temperature, no matter how cold or hot their surroundings may be. There are nearly 4,000 species of mammal, and most of these have hair or fur on their bodies. Except for the platypus and echidna, all mammals give birth to live young. Unlike other animals, they feed their young with milk. Mammals Evolved from reptiles that had several bones in the lower jaw. Types of Mammals The three main groups of mammal are; monotremes marsupials placental mammals Monotremes (the platypus and echidna) have many features in common with mammals' reptile ancestors. They have a single opening, called a cloaca , for reproduction and body wastes, and they lay eggs. Female ...