What’s the Difference Between a Mammal, a Marsupial or a Monotreme?

Posted by Roberta Goli Sep 12, 2009

Do you know the difference between a mammal, a marsupial or a monotreme? Don't feel bad if you don't, it can be confusing, but there are a few simple things that set them apart.

Some Mammalian characteristics are:

• All mammals have hair somewhere on their body (even marine mammals, it's just not easily visible).
• Mammals are warm-blooded animals.
• The word mammal is derived from the words mammary glands and female mammals have them.
• Mammals breath air via lungs (yes, marine mammals too!)

Some examples of mammals are monkeys, bears, humans, koalas, whales, mice, horses, dogs, cats, cheetahs, camels, elephants, bats and the list could go on. With over 4600 species, mammals are pretty diverse!

Marsupials and monotremes still fall under the Class Mammalia, but while most mammals give birth to live young, the marsupials and monotremes do it a little differently.

• Marsupial young are born live but continue their development inside the mother's pouch. An example of a marsupial is the kangaroo.
• Monotremes are a small group of mammals that lay young inside of egg. An example of a monotreme is the duck-billed platypus.

To learn more about the differences and similarities between the mammals, marsupials and monotremes, read Mammals, Monotremes and Marsupials: Mammalian characteristics and the Diversity of Mammals