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Marsupial

Marsupials are a group of mammals in the infraclass Marsupialia (also called Metatheria).

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 26, 2026|2 min read| Fact-checked

Marsupials are a group of mammals in the infraclass Marsupialia (also called Metatheria). Their young are born very underdeveloped and continue development while attached to the mother’s nipples; many species also use a pouch, or marsupium, to carry and protect the young.

Classification

Marsupials are placed in the infraclass Marsupialia, which is also called Metatheria. They are one of the major living lineages of mammals.

Reproduction

Marsupial young are born at a very early developmental stage and usually complete much of their growth while attached to nipples on the mother’s body. A pouch is common but not present or equally developed in every species.

Distribution and diversity

Living marsupials are native to Australasia, Wallacea, and the Americas. More than 250 extant species are known, including a wide range of body sizes and lifestyles.

Examples

Well-known marsupials include kangaroos, wallabies, koalas, wombats, opossums, bandicoots, Tasmanian devils, and possums. These animals illustrate the ecological and physical diversity of the group.

Key facts

  • Marsupials are mammals distinguished by premature birth and continued development after birth.
  • Most female marsupials have a pouch, but some species have a reduced pouch or none at all.
  • The term comes from the Latin marsupium, meaning pouch.
  • Marsupials occur naturally in Australasia and the Americas, with the greatest diversity in Australia and nearby regions.
  • Common examples include kangaroos, koalas, wombats, opossums, and Tasmanian devils.
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Canadian context

Marsupials are not native to Canada, but they are commonly studied in Canadian biology, zoology, and comparative mammal courses as an important mammalian group distinct from placentals.

Frequently asked questions

What is a marsupial?
A marsupial is a mammal in the infraclass Marsupialia, characterized by the birth of very undeveloped young that continue developing after birth.
Do all marsupials have pouches?
No. Many species have a pouch, but it is not universal; some have a reduced pouch or no obvious pouch.
Where do marsupials live?
Extant marsupials are native to Australasia, Wallacea, and the Americas.
How many marsupial species are there?
Sources commonly describe marsupials as having more than 250 living species.
What animals are marsupials?
Examples include kangaroos, koalas, wombats, opossums, wallabies, bandicoots, Tasmanian devils, and possums.

References

  1. Encyclopaedia Britannica — https://www.britannica.com/animal/marsupial
    Supports: Definition, classification, reproductive traits, diversity, and pouch explanation.
  2. Encyclopedia.com — https://www.encyclopedia.com/plants-and-animals/animals/vertebrate-zoology/marsupials
    Supports: Definition, pouch etymology, and general characteristics of marsupials.
  3. Merriam-Webster — https://www.merriam-webster.com/dictionary/marsupial
    Supports: Dictionary definition and note that females usually have a pouch.
  4. Wikipedia — https://www.wikipedia.org/wiki/Marsupial
    Supports: Broad overview of distribution, examples, and evolutionary context.