Bandicoots and Bilbies: Peramelemorphia

Most species in this order are nocturnal, active only at night. The exception is the southern brown bandicoot, which is active mainly during the day. All members of this order live alone, coming together only for a short time to mate. Females will mate with more than one male. Many species mate year round. Both males and females are territorial. Males have larger territories than females. Some species mark their territory with scent from a special gland. Males become aggressive when another male enters their territory. Males kept together in captivity will fight.

Most familiar mammals such as dogs, rabbits, and horses, are called eutherian (yoo-THEER-ee-an) mammals. These mammals have a placenta, an organ that grows into the mother's uterus (womb) and lets the mother and developing offspring share food and oxygen until the organs of the developing young mature. Marsupial mammals do not have this type of developed placenta. Most marsupials have what is called a yolk-sac placenta, where there is no sharing of the mother's food and oxygen.

Bandicoots and bilbies are different from other marsupials, because they have a second placenta in addition to the yolk-sac placenta. This placenta resembles the placenta in eutherian mammals, but does not function as well, because it does not attach as closely to the wall of the mother's uterus. As a result, members of the order Peramelemorphia have very short pregnancies, and, like other marsupials, the young are physically immature and undeveloped when they are born. At birth they crawl to their mother's backward-opening pouch where they attach to the mother's teats, or nipples. They are carried inside the pouch until they are mature enough to survive independently.