What is unusual about the way marsupials give birth?

Answer 1

The differences are that placental have embryos that develop inside the mother body. The embryo grows in the placenta, which attaches the embryo to the uterus. The placenta carry's food and water to the mothers blood and carries waste from the embryo. A female monotreme lays eggs then uses energy to keep the eggs warm. She feeds them milk when they hatch. Of course, monotremes do not have nipples, so the babies lick the milk from the skin and hair around their mothers mammary glands. Finally, marsupials give birth to live young. Until big enough, marsupial babies or newborns are carried in a mothers pouch for several months.

Answer 2

Marsupials give birth to live young that are characterised by being extremely small, hairless and undeveloped. At birth, they take a long, arduous journey from the birth canal, driven purely by instinct, to reach the pouch, where they stay for months, to complete their development.

Answer 3

Most mammals of the world are developed in the womb attached to their mothers by the placenta, just as humans. These mammals are called Placentals and all their needs through early development are taken care of through the placenta. In Marsupials there is no placenta. The development of the foetus takes place largely outside of the womb. Not long after conception a tiny foetus about the size of a newly born mouse crawls from the birth canal up through the fur and into the pouch. Here the tiny new life attaches itself to a teat and remains there, filling up on the rich milk and growing quite fast. In the case of a Kangaroo, after about 8weeks the joey will start to make an appearance and in a few more weeks will leave the pouch for ever. This triggers another tiny life to emerge and the cycle continues. Kangaroos are permanently pregnant

Answer 4

Marsupials are mammals with unique adaptations that make them different from placental mammals in several ways.

Marsupial young are born very undeveloped. Moving purely by instinct, the baby joey (the term for all marsupial young) makes its way to the mother's pouch, where the young joey latches onto a teat, remaining there to continue its growth and development.

Many female marsupials have the mammary glands enclosed within a protective pouch. Although a mammal with a pouch is always a marsupial (with the exception of the echidna, which develops a rudimentary pouch during breeding season), not all marsupials have pouches: for example, the numbat of Western Australia and the brown antechinus do not have pouches.

All marsupials are mammals, but not all mammals are marsupials. Marsupials do not have advanced placentas, and have epipubic bones (with the exception of the marsupial mole). Epipubic bones are bones which project forwards from the pelvis. In the case of marsupials, these bones support the female's pouch, but there are other mammals which are not marsupials which also have epipubic bones. The excretory and reproductive systems of placental mammals and marsupials are also different.

Female 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. Most male marsupials, with the exception of the largest species, the Red Kangaroo, Eastern Grey and Western Grey Kangaroos and one of the smallest species, the Honey Possum, have a two-pronged penis to accommodate the females' two vaginas.