Mammalian is a term used to describe animals who possess mammary glands and give live birth to their young ones. There are many synonyms for the word mammalian, some of them include: vertebrates, warm-blooded, viviparous, therian, eutherian, placental, and milk-producing. The term "vertebrates" encompasses all animals that possess a backbone, while "warm-blooded" refers to animals whose internal body temperature remains constant irrespective of the environment. Some other synonyms for mammalian include "viviparous" which refers to animals that give birth to live offspring. "Therian" denotes the subclass of mammals that includes marsupials and placental mammals, while "eutherian" refers to a subclass of placental mammals.