Their teeth are small needle-like incisors. If you think marsupials are animals that have pouches and live in Australia, you're wrong. Most female marsupials carry their young in an abdominal pouch called a marsupium. You might be surprised to learn that some pouches open to the rear. This makes sense if you consider that a nursing marsupial in a pouch opening to the front might be poked with sticks and sharp grasses if its mother walked on all fours.
Many marsupials develop pouches only during the breeding season.
Their young are generally born tiny, blind, hairless, and nearly helpless. A newborn marsupial's first great adventure is the long crawl to its mother's mammary glands. The nipple expands in the young's mouth, helping it maintain a secure grip to its mother. Most marsupials have 40-50 teeth, more than most other mammals. Since marsupials seem to have simpler brains they haven't fared too well in the face of competition with other mammals.