A wallaby has an incredible reproduction system. It starts off much like that of a human: an egg is ovulated from the ovaries of the mother wallaby and waits for fertilization. Once fertilized, it plants itself into the uterine wall of the mother. However, this is where the similarities to human reproduction end. A joey (baby kangaroo or wallaby) is born after 28 days. It’s much more similar to a bird at this point; it eats all the yolk in the egg to sustain itself, and hatches.
This is where it gets really interesting. Once the egg hatches, the baby exits the mother by the tail and climbs its mother so that it can develop in the pouch. A newborn joey is tiny! It’s not very developed, either, but after 8 months in the pouch, it’s about as developed as a newborn human.
