MARSUPIALS: THE POUCH LIFE
Marsupial pregnancies begin in the uterus. Rather than developing a placenta, marsupial young leave the uterus between two and four weeks into the pregnancy, depending on species. These very undeveloped, hairless newborns share one well-developed feature: forelimbs with claws. The young climb from the mother’s birth canal into the pouch, where they fuse to her nipples. They are nourished by their mother’s milk and breathe the warm, moist pouch air, which has a different composition than outside air. The mother’s milk changes as her babies’ needs change, and as they become old enough to venture outside the pouch, they detach from the nipples. Older babies live outside the pouch but return to nurse for some time.
1. Red Kangaroo: Embryo Outside the Womb? Some day this little guy or girl will be about as tall as a man. But for now the weeks-old red kangaroo joey is roughly cherry-size, essentially an embryo outside the womb.
2. Bandicoot from My Animal Planet
3. Wallaby embryo in mother’s pouch. A newborn tammar wallaby climbs towards its mother’s pouch.
4. Wallabies give birth to very immature, almost embryonic, young that complete most of their development attached to the teat, usually within a pouch. (Credit: Kathleen Röllig)
5.Pygmy Possum newborn in human palm, clearly demonstrating typical marsupial small size at birth but with relatively well developed forearms