A baby kangaroo is called a "joey." The term originates from the Australian Aboriginal language, specifically the Eora language of Sydney. Joeys are born very small and immature, often less than an inch long, and they continue to develop in their mother's pouch for several months. Pouch life is crucial for their survival as they are protected from environmental dangers while they grow and develop. The term "joey" can also refer to the young of other marsupials, but it is most commonly associated with kangaroos.