The class Mammalia (mammals) is divided into two subclasses based on reproductive techniques: monotremes, which lay eggs, and therians, mammals which give live birth, which has two infraclasses: marsupials (pouched mammals) and placental mammals. See List of monotremes and marsupials, and for the clades and families, see Mammal classification. Classification updated from Wilson and Reeder's Mammal Species of the World: A Taxonomic and Geographic Reference using the Planet' Mammifères website.[1]