Pouch (marsupial)

The pouch is a distinguishing feature of female marsupials and monotremes,[1][2][3] and rarely in males as well, such as in the yapok[4] and the extinct thylacine.

The kangaroo's pouch opens horizontally on the front of the body, and the joey must climb a relatively long way to reach it.

Similarly, forward-facing pouches would not work well for wombats and marsupial moles as they both dig extensively underground.

[5][6] In a relatively short time, the cleansing droplets clean out all of the crusty material left inside, leaving an almost sterile environment ready to receive the tiny joey.

The water opossum and the now extinct Tasmanian tiger are the only two marsupials where the male also has a pouch (in order to protect their genitalia while swimming).

Instead, they form temporary skin folds (sometimes called "pseudo-pouches") in the mammary region when reproducing.