image: A tammar wallaby joey peeks out of its mother's pouch at the Smithsonian’s National Zoo on May 30, 2008. Tammar wallabies are marsupials -- like kangaroos -- and after birth, offspring climb into their mothers' pouch and where they nurse and continue developing over several months. Keepers first noticed the joey’s head emerging from the pouch in March. They estimate it is now seven months old. Not wanting to disturb the delicate bond between the mother and baby, keepers have yet to separate them for an exam to determine its sex and weight. view more
Credit: Mehgan Murphy/Smithsonian's National Zoo