Here's a bit more detail:
* Kangaroos, Wallabies, and other marsupials give birth to very underdeveloped young.
* These young joeys climb into their mother's pouch immediately after birth and stay there for several months, where they continue to develop.
* The pouch provides a safe, warm, and nourishing environment for the joey to grow.
* As the joey grows, it spends less and less time in the pouch until it is finally weaned and independent.
So, in short, baby joeys live in their mother's pouch!