Definition

1. Noun:
   • A mammal that gives birth to relatively mature, live young after a long gestation period, during which the embryo is nourished by a placenta: This term refers to all placental mammals, which constitute the vast majority of living mammal species. It excludes monotremes (egg-laying mammals) and marsupials (mammals whose young complete development in an external pouch).

Usage Examples

• Noun:
  • Humans, dogs, and whales are all examples of a eutherian mammal.
  • The fossil record shows that the eutherian mammal diversified after the extinction of the dinosaurs.
  • Unlike a kangaroo, a cat is a eutherian mammal whose offspring are born in a more developed state.

Advanced Usage

• In evolutionary biology, the term eutherian is often used as a noun to refer to the group itself.
  • The divergence between eutherians and marsupials occurred millions of years ago.
• The adjective form eutherian describes characteristics of this group.
  • The eutherian reproductive strategy involves a complex placenta.

Variants and Related Words

• Eutherian (adj/n): Pertaining to placental mammals; also used as a synonym for "eutherian mammal."
  • Eutherian embryos develop differently from marsupial embryos.
• Placental mammal (n): A direct synonym for eutherian mammal.
• Placentalia (n): The scientific infraclass name for this group.

Synonyms

• Placental mammal: The most common direct synonym.
• Placental: A shortened, informal form used in scientific contexts.

Related Terms (Conceptual)

• Metatheria: The infraclass containing marsupials.
• Prototheria: The subclass containing monotremes (egg-laying mammals like the platypus).
• Placenta: The organ that nourishes the developing fetus, defining this group.

Noun

1. mammals having a placenta; all mammals except monotremes and marsupials