Let me share with you a difference between metatheria and Eutheria.
| Aspect | Metatheria | Eutheria |
| Known as | Marsupials | Placental mammals |
| Reproduction | Live birth and offspring continue development in a pouch. | Live birth and offspring fully develop inside the uterus and get nutrition through placenta. |
| Gestation period | Short gestation period usually of few weeks | Longer gestation period |
| Placenta | Simple, short-lived placenta or absent | Well-developed, complex placenta |
| Geographic distribution | Predominantly in Australia and the Americas | Widespread globally |
| Number of Species | Diverse group with a significant number of species | Largest group of mammals with the highest number of species |
| Lifespan | Shorter lifespan | Longer lifespan |
| Examples
| · Kangaroos · Koalas · Opossums
| · Humans · Dogs · Cats · Elephants |