Marsupial

Marsupials are mammals in which the female typically has a pouch in which it rears its young through early infancy. They belong to the subclass of Mammalia known as Metatheria?.

Marsupials differ from placental mammals (Eutheria?) in their reproductive traits. The female has two vaginas, each of which leads to a different compartment in the uterus. Males usually have a two-pronged penis which corresponds to the females two vaginas. The pregnant female develops a kind of yolk sack in her placenta which delivers nutrients to the embryo. The embryo is born at a very early stage of development (at about 4-5 weeks), upon which it crawls into the mother's pouch and attaches itself to a nipple. It remains attached to the nipple for a number of weeks. The offspring later passes through a stage where it temporarily leaves the pouch, returning for food and nourishment.

There are between 260 and 280 species of marsupials. They are commonly found in Australia and New Zealand. There are also many extant species in South America and one species, the Virginia opossum, native to North America.

Marsupials include:

• Kangaroo
• Koala
• [Sugar glider]?
• Wombat

Extinct:

• Thylacine ("Tasmanian wolf")