Many people wonder about the unique reproductive biology of possums, particularly whether these mammals possess a specialized structure for raising their young. This inquiry often leads to questions about a specific anatomical feature.
Possums and Their Pouches
Most female possums possess a pouch, a specialized abdominal fold of skin known scientifically as a marsupium. Both Australian ‘possums’ (suborder Phalangeriformes) and American ‘opossums’ (order Didelphimorphia) are marsupials. Marsupials give birth to highly underdeveloped young that complete early development within this external pouch.
The marsupium serves as a warm, protective incubator for the newborn, often called a joey, where it can continue its development. Inside, mammary glands with teats provide nourishment. While the pouch structure varies slightly, its purpose remains consistent: to provide a secure environment for the underdeveloped young. This adaptation defines marsupial reproduction and parental care.
Life in the Pouch and Beyond
Marsupial young are born in an extremely embryonic state, often no larger than a jelly bean and weighing less than a gram. Immediately after birth, this tiny, blind, and hairless joey instinctively crawls from the birth canal, across the mother’s fur, and into the safety of the pouch. Opossum joeys, for instance, are born after a gestation period of only 12 to 14 days.
Once inside the marsupium, the joey locates and firmly latches onto one of the mother’s teats. The teat swells, securing the joey and ensuring a continuous milk supply for several weeks or even months, depending on the species. For opossums, joeys remain attached to the teat for several weeks and typically stay in the pouch for about 2 to 3 months. During this period, the joey grows rapidly, developing its fur, eyes, and limbs within the secure confines of the pouch. Their eyes typically open around 55-70 days.
After significant development, the joey begins emerging from the pouch for short periods. Initially, excursions are brief, with the joey quickly retreating for warmth and safety. Gradually, as the joey becomes more agile and independent, it spends more time outside the pouch, often riding on its mother’s back or clinging to her fur. Joeys are typically weaned around 3 months of age and become fully independent at approximately 4.5 to 5 months old.