Kangaroos usually reproduce during the rainy season and give birth 30 days after conception. The joey, as kangaroo offspring are called, transfers to the mother's pouch and resides there for one to one and a half years after birth.
The doe, or female kangaroo, is able to control when she becomes pregnant to avoid having two joeys at the same time. If her offspring dies or matures enough, she is able to get pregnant again. During the dry season, kangaroos are unable to reproduce, as bucks, or male kangaroos, often can't produce sperm during this period.
When joeys are born, they are able to climb into the mother's pouch and suck milk from her body despite being the size of a lima bean. Females have four nipples for milk and have very strong muscles around their pouches to protect their young. A doe can get pregnant again while a joey is still in her pouch and produces two types of milk for each offspring. She is also able to determine the sex of her offspring and prefers to give birth to females when she is young and males when she gets older.
Female kangaroos form a close bond with their joeys, and they seem to become sad when they age and cannot reproduce anymore. Once they are older, they may spend more time with younger females that have their own joeys.