A "joey" is the baby of what animal?

The term for a baby animal known as a "joey" is most famously applied to the young of Australia's iconic kangaroo. A newborn kangaroo is remarkably underdeveloped, often no larger than a jellybean and weighing less than a gram. Immediately after birth, this tiny, blind, and hairless creature undertakes a perilous journey, crawling unassisted from the birth canal up its mother's fur and into the safety of her pouch, or marsupium. Inside this warm pocket, the joey latches onto a teat and continues its development for several months.

As the joey grows, it begins to peek out at the world before eventually taking its first tentative hops outside. For many more months, it will continue to use the pouch as a home base, diving back in headfirst for safety, warmth, or a quick drink of milk. It's a common sight to see a large, gangly joey with its legs dangling out of a pouch that seems far too small to contain it.

While inextricably linked with kangaroos, the name "joey" is not exclusive to them. Believed to derive from an Aboriginal Australian word for "small animal," the term is correctly used for the young of most marsupials. This includes close relatives like wallabies and wallaroos, as well as other pouched mammals such as koalas, wombats, and even the opossums native to the Americas.