1. 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.