What are the Differences Between Mammals and Marsupials?
There are three groups of mammal: placental mammals, marsupials, and monotremes. Monotremes only include the platypus and four species of echidna. The remaining mammals are all placentals or marsupials. The placental mammals are clearly dominant, as they have been for over 65 million years, with over 5,500 species on every continent except Antarctica. The marsupials, with only 334 species, has carved out a niche for itself in Australia, where it has largely displaced placental mammals. Marsupials are also found in small numbers in South America and Central America, with a single species (Virginia Opossum) in North America. Marsupials and placental mammals are both mammals, that is, warm-blooded tetrapods with sweat glands that provide milk for young and are covered in a layer of fur or hair. What distinguishes the two from each other are 1) their mode of reproduction, 2) genitalia, and 3) their blood temperature, which is slightly less than that of placental mammals. For many centuries
