noun
- mammals that nourish their young through a placenta during pregnancy
Usage: biological term; plural form
Examples
- Placentals include humans, dogs, cats, and most familiar mammals.
- The evolution of placentals allowed for longer gestation periods.
- Scientists study the reproductive strategies of placentals versus marsupials.
- Placentals dominate most terrestrial ecosystems around the world.
- The fossil record shows placentals diversified rapidly after the dinosaur extinction.
- Marine placentals like whales and dolphins adapted to aquatic life.