This article is about the subclass of mammals. For the use of the word "therian" as a synonym for "therianthrope", used predominantly in the context of modern subcultures, see "Therianthropy (subculture)".

Theria (pronounced from the Greek θηρίον, wild beast) is a subclass of mammals that give birth to live young without using a shelled egg, including both placentals and marsupials. They have external ears, can suckle on a nipple, and have an ankle specialized for power and range of motion. Therians are often classified by their specialized dentition. Almost all currently extant mammals are therians. The only exceptions are the platypus and the echidnas (spiny anteater), both of which are monotremes. Theria means beasts.

Mammals

Teri | Theria | Theria | Vivonaskuloj | Thériens | 수아강 | Elevenszülő emlősök | Theriiformes | Theria | Ssaki żyworodne | Theria