Säugetägets

Säugetägets is a term used in a small number of zoological and popular-science writings to refer to the group of animals known as mammals. It is not an official taxonomic name and is not recognized by major nomenclatural codes; its usage is informal and varies by author.

Definition and scope: In most non-peer-reviewed uses, Säugetägets denotes the crown group Mammalia or a closely related informal clade. Some authors place monotremes (platypus and echidnas) within Säugetägets, while others reserve the term for therian mammals (marsupials and placentals) only. The defining features typically cited are mammary glands, hair, endothermy, and three middle ear bones; most members also give birth to live young, though monotremes lay eggs and challenge a simple definition.

Evolution and fossil record: Mammal-like synapsids appeared in the Late Triassic, with true mammals emerging by the Middle to Late Jurassic. The later Cretaceous–Paleogene periods witnessed major diversification of mammals.

Distribution and ecology: Today, Säugetägets comprises a globally distributed and ecologically diverse group, occupying terrestrial, arboreal, marine, and aerial niches; many species are apex or mesopredators, herbivores, or omnivores.

Note: The term is informal and not used in standard taxonomic references; readers should consult primary sources for authoritative definitions if Säugetägets appears in a text.