What are the differences between a monotreme and a marsupial?

Answer 1

Marsupials and monotremes are mammals. These creatures all feed their young on mothers' milk.

If the question means what is the difference between placental mammals (eutherians) and marsupials and monotremes, that is another matter. The essential difference between all of the groups is that placentals nurture their developing young via the placenta inside the female's body.

Most marsupials (not all) have a pouch, or marsupium, low down on their abdomen into which the newborn, undeveloped joey crawls after birth to continue its development. Monotremes, on the other hand, are egg-laying mammals.

Answer 2

A marsupial is a pouched mammal. The pouch is where the young joey undergoes most of its growth and development. The tiny, bean-sized joey crawls into the pouch where it latches onto a teat. The teat swells in its mouth, preventing it from being accidentally dislodged while the mother moves around.

A monotreme is an egg-laying mammal. The young are not born, but hatched. The echidna actually lays its egg straight into a fold of skin, like a pouch, that develops only during breeding season, and this is where the egg is incubated. Soon after hatching, the young echidna is transferred into a burrow. The platypus, the other monotreme, lays its egg/s in a burrow or chamber, and does not have a pouch of any description.

Like placental mammals, both marsupial young (which are called joeys) and monotreme young (which do not have a particular name) feed on mother's milk.

Answer 3

Monotremes, after a gestation period of about ten days, lay an egg. Several days later, the egg hatches, and a somewhat developed baby emerges. Marsupials, after a gestation period of about two weeks, give live birth (no egg) to very undeveloped young. The young then climb and cling to the mother's nipple, without leaving it, for several more weeks (or months). The nipple may or may not be inside a pouch to protect the young.