Kangaroos, iconic symbols of Australia, are known for their powerful hind legs and distinctive method of raising their young. A common question concerns the name for their offspring.
What They Are Called
Baby kangaroos are known as joeys. This term applies to the young of many other marsupials, a group of mammals characterized by carrying their young in a pouch. The offspring of wallabies, koalas, wombats, opossums, and Tasmanian devils are also called joeys. The origin of “joey” is not definitively known, but it may have been a diminutive used historically for any small animal.
The Early Life of a Joey
The birth and initial development of a joey represent a remarkable biological adaptation. After a short gestation period, typically 28 to 40 days, a kangaroo gives birth to an incredibly underdeveloped offspring. At birth, the joey is tiny, often compared to the size of a jellybean, measuring only about 2 centimeters (approximately 1 inch) long and weighing less than a gram. This miniature, blind, and hairless creature has disproportionately developed forelimbs with claws.
Immediately after birth, driven by instinct, the joey embarks on an arduous, unassisted climb through its mother’s fur to reach her pouch. The mother prepares for this journey by licking a path, which the joey follows using its strong sense of smell. Once inside the warm, moist pouch, the joey latches onto a nipple, which swells to secure it in place. It remains firmly attached for several weeks, continuously suckling and developing. The pouch itself is hairless, soft, and warm, providing a sheltered nursery.
Growing Up and Out of the Pouch
As the joey grows, its development progresses within the mother’s pouch, but its world gradually expands. Around four to six months of age, the joey begins to peek its head out, observing its surroundings for the first time. These initial excursions are brief, with the joey quickly retreating into the pouch for safety or nourishment. Over the next few months, the joey’s trips outside the pouch become longer and more frequent, allowing it to explore, graze on vegetation, and practice hopping. Even as it spends more time outside, the joey continues to return to the pouch for warmth, protection, and milk.
Kangaroos are able to produce different types of milk tailored to the developmental needs of joeys of different ages simultaneously. Joeys typically leave the pouch permanently between 8 to 11 months, depending on the species, but they may continue to nurse from their mother for several more months, sometimes up to 12 to 18 months of age, before becoming fully independent.