12.3.2. Marsupials

♤ Marsupials are the group of mammals commonly thought of as pouched mammals (like the wallaby and kangaroo).

♤ Marsupial mammals have placenta but it is very shortlived and does not make as much of a contribution to fetal nourishment.

♤ They give birth very early and the young animal, essentially a helpless embryo, climbs from the mother’s

birth canal to the nipples.

♤ There it grabs on with its mouth and continues to develop, often for weeks or months depending on the species.

♤ They do not have long gestation times like placental mammals. The short gestation time is due to having a yolk-type placenta in the mother marsupial.

♤ Extinct - Marsupial - quagga, the marsupial wolf .

♤ Placental mammals all bear live young, which are nourished before birth in the mother’s uterus through a specialized embryonic organ attached to the uterus wall, the placenta.

♤ Placental mammals nourish the developing embryo using the mother’s blood supply, allowing longer gestation times.

Do you know?

Not all sharks are fierce carnivores. Some are quite harmless. Oddly enough, the most harmless sharks tend to be the largest! The basking shark, the whale shark and the Mega mouth sharks all fit this description. These huge sharks eat plankton.