Kangaroos belong to a class of mammals called marsupials. They are different from other mammals because they are born at a very early stage of development and that’s why they are carried around inside the pouch. The embryo spends very little time inside the mother’s body (about a month’s time) and climbs up to the mother’s pouch coming out of the her reproductive tract. The pouch is where they get their milk. Only about six months after birth, young one leaves the pouch.
When a kangaroo tries to walk or move slowly, tail acts as a fifth leg. Balancing with the help of tail, it moves forward slowly with its smaller forelegs. They cannot walk on all the four legs because except while swimming, kangaroos cannot move their hind legs independently of each other.