Eastern grey kangaroos (Macropus giganteus). Young kangaroo (right) with its mother (left). As a marsupial, a female kangaroo gives birth to an under-developed young (joey) that develops in the mother's pouch. The joey feeds on its mother's milk for around 300 days and will often return for protection or milk after leaving the pouch. An adult feeds mainly on vegetation. The large hind legs allow a kangaroo to move with great speed in a bounding motion. It is mostly nocturnal, but is also active at dusk and dawn. Photographed at Narawntapu National Park, in Tasmania, Australia.