Mammals are dominant animals that inhabit diverse environments. Their distinctive features are milk-producing mammary glands, hair on the body, sweat glands, external ear and a diaphragm. They produce two sets of teeth. Egg laying mammals are called monotremes and pouched mammals are called marsupials.Mammals are viviparous with the exception of two egg laying mammals, the platypus and echidna. Egg laying mammals are platypus, short beaked echidna, western beaked echidna and long beaked echidna. Pouched mammals are like kangaroo, black shouldered opossum, bushy tailed opossum,white eared opossum, water opossum, white eared opossum and bare-tailed wooly opossum.