In Brave Koala, a young koala decides he is ready to explore the world by himself. The koala is a marsupial -- a mammal that raises its young, called a joey, in a pouch or fold of skin. A newborn joey climbs through its mother's fur to the pouch, where it stays for 6 months. When a joey leaves the pouch, it will stay with its mother, hitching rides on her back, until it is about 12 months old.