Placental Mammal Here

The next time you see a mammal, remember the incredible biological engineering—the placenta—that allowed them to become the dominant group they are today.

While the exact "first" placental is debated, fossil evidence suggests a massive explosion in their numbers shortly after the extinction of the dinosaurs about 65 million years ago. They quickly filled the ecological niches left behind, eventually spreading to almost every habitat on Earth. Quick Comparison: Mammal Reproductive Types Marsupial Monotreme Birth Style Live birth (Mature) Live birth (Underdeveloped) Early Care Internal (Placenta) External (Pouch) Egg Incubation Examples Kangaroos , Opossums Platypus , Echidna placental mammal

: Some placentals, like fawns or foals, can literally stand up and walk within hours of being born. The next time you see a mammal, remember