Why are koalas called marsupials?

Answer 1

Koalas are called marsupials, and not bears, because that is what they are - marsupials. They are not related to bears in any way; and bears are placental mammals, not marsupials.

Like most (not all) marsupials, koalas have a pouch in which to keep their young. Most marsupials, including kangaroos, wallabies, possums, bandicoots and koalas, share this feature, but some marsupials such as the numbat have just a rudimentary flap of skin to protect the joeys.

Like other marsupials, koala joeys are characterised by being extremely small and undeveloped at birth. At birth, they take a long, arduous journey from the birth canal, driven purely by instinct, grabbing hold of the mother marsupial's fur to reach the pouch. Upon reaching the pouch, they latch onto a teat which swells in their mouth to prevent them from being accidentally dislodged during the mother's movements. There they stay for months, to complete their development.

Female koalas, like other marsupials, have two vaginas, or what are called paired lateral vaginae. These are for the purpose of transporting the sperm to the womb, but there is a midline pseudovaginal canal for actually giving birth. As well as two vaginas and two uteruses, female marsupials have two fallopian tubes and two cervixes. Male koalas are like most male marsupials (except for the largest species, the Red Kangaroo, Eastern Grey and Western Grey Kangaroos), in that they have a bifurcated, or two-pronged penis, to accommodate the females' two vaginas.