A newborn kangaroo is only the size of a jellybean.

A Red Kangaroo is born after only 33 days of pregnancy. At birth, the baby weighs less than one gram and cannot see. It has no hair and its back legs are just small bumps. However, its front legs are strong enough to climb through the mother's fur. It uses its sense of smell to find the pouch, which is a journey of about 6 inches.The climb takes three to five minutes. Once inside, the baby attaches to a nipple. The nipple swells in the baby's mouth to keep it safely in place. The mother's milk changes its ingredients as the baby grows. This ensures the joey gets the right nutrients at every stage of its life.Kangaroos can also pause a pregnancy. This is called embryonic diapause. If the mother is already nursing a baby or if there is a drought, she can stop a second embryo from growing. The joey stays in the pouch for about 190 to 235 days. Even after it leaves, it returns to the pouch to drink milk for up to a year.This system helps kangaroos survive in Australia. Giving birth to a tiny baby uses less energy than a long pregnancy. If a baby does not survive, the mother can quickly start growing the paused embryo. This makes kangaroos very efficient at raising young in harsh environments.