What is the life cycle of a wallaroo?

Answer 1

Wallaroo joeys (joey being the name for any baby marsupial) are born about 2cm long. The joey emerges from the birth canal, just as any mammal young does, but it is very undeveloped, completely blind and hairless, and cannot survive for any length of time outside its mother's pouch. Moving by instinct only, it crawls up the mother's fur to the pouch, where it attaches to a teat. The teat then swells in the joey's mouth, securing it through all the mother's movement so it cannot be dislodged, until it has grown for several weeks.

Wallaroo joeys spend at least 6 months in the mother's pouch before they star making forays out into the world. After they leave the pouch for good, they continue to be nursed for another couple of months, only placing just their heads in the mother's pouch to suckle until weaned.

In the initial stages, the joey stays attached to the teat until it is ready to begin being independent. A mother wallaroo is capable of supporting one joey in the pouch and another joey at foot living permanently outside the pouch but still suckling. When nursing both a joey at foot and a joey in the pouch, the mother produces a different milk concentration for each joey, as each joey has its own teat. Wallaroos and other macropods produce colostrum throughout the entire joey stage, unlike placental mammals that only provide colostrum for a few days after birth.

Wallaroos have "embryonic diapause". This means that the mother can become pregnant soon after birth, but can suspend the development of the joey when it is still an embryo within her body, awaiting a time when conditions may be better suited for the birth of the young joey (for example, if she is already nursing a joey in the pouch or during drought times). This is why female wallaroos of reproductive age spend all of the adult lives pregnant.

Wallaroos live an average of 17 to 19 years in the wild.