The joey is in the mother kangaroo's pouch for about eight months, depending on the species. Sometimes a mother kangaroo will have two young of two different ages in her pouch at the same time. When this happens, she is able to produce different milk for each, depending on their age. Female kangaroos are in an almost permanent state of pregnancy, but they have "embryonic diapause", meaning they can suspend the development of the next embryo until conditions are right for it to be born (e.g. plenty of food).
A male kangaroo is called a boomer. A female kangaroo is called a flyer. A baby kangaroo is called a joey. Baby kangaroo, or joeys, are born from the mother's birth canal at the base of the tail. Although blind, hairless and completely helpless, the joey (about the size of a bean) clings to its mother's fur, making a long and arduous journey completely by instinct, up to the pouch. The mother aids this journey by licking a pathway from the birth canal to the pouch. Once there, the joey attaches its mouth to a teat, which swells in its mouth to prevent it from being accidentally dislodged.