There are currently 1,258 genera, 156 families, 27 orders, and around 5,937 recognized living species of mammal. Mammalian taxonomy is in constant flux as many new species are described and recategorized within their respective genera and families. The taxonomy represented here is a compilation of the most logical and up-to-date information on mammalian taxonomy from many sources, the main ones being Handbook of the Mammals of the World series and Mammal Species of the World.