The life cycle of the possum, or joey, is a progression marked by dramatic physical transformation, which is typical for marsupials. The young changes completely as it moves from a nearly embryonic state at birth to a fully mobile juvenile ready for independence. This developmental journey moves rapidly from the safety of the pouch to riding on the mother’s back before the young possum ventures out on its own.
The Newborn Stage
Following the short gestation period, the newborn possum is strikingly underdeveloped, often referred to as a “pinky.” At birth, the joey is tiny, weighing less than a gram and measuring about the size of a dime. Its initial appearance is embryonic, characterized by translucent, pink skin that is completely hairless.
The eyes are sealed shut, and the ears are barely formed, appearing only as small dark spots beneath the skin. The hind limbs are underdeveloped buds, but the forelimbs are robust, equipped with sharp, temporary claws. These specialized front paws are used exclusively to drag the neonate from the birth canal up the mother’s fur and into her abdominal pouch.
Physical Changes Inside the Pouch
Once securely latched to a teat inside the pouch, the joey undergoes rapid growth. After about a week of constant suckling, the babies may triple their size and increase their birth weight tenfold. For the first several weeks, they remain permanently attached to the nipple, which swells to hold them in place.
Around 50 to 70 days into their pouch development, the young possums reach a point of significant physical change. They begin to develop fine hair, their sealed eyes start to open, and their ears become more pronounced and leathery.
The joey grows to about the size of a small mouse and starts to detach from the nipple for short periods, gaining the ability to chew solid food. Though still protected within the pouch, the developing young possess a coat of coarse, gray fur and resemble the adult possum in miniature.
Appearance of the Juvenile
The juvenile possum changes markedly once it is too large for the pouch and begins riding on the mother’s back. At this stage, typically three to four inches long excluding the tail, the young possum has a fully developed, though still small, coat. The fur is often a puffy, grayish-white mixed with darker guard hairs, giving them the characteristic adult coloration.
The head displays the iconic possum features, including a pointed, pale snout and prominent, hairless black ears. Their dark, button-like eyes are fully open, and they are highly alert and mobile as they cling to their mother. The juvenile’s prehensile tail is a defining feature, appearing long, scaly, and naked, used like a fifth limb to grasp the mother’s fur or surrounding branches.
As they transition to independence, the juvenile possums are smaller and less robust than the adult, generally measuring six to eight inches in length from nose to rump. They are fully furred and look like tiny versions of the mature possum, but their reliance on the mother distinguishes them from solitary adults. Once they weigh over 200 grams, they are fully equipped to survive independently.