Koala dominant. Older males usually have accumulated scratches, scars, and cuts on the exposed parts of their noses and on their eyelids. The koala's gestation period lasts 33–35 days, and a female gives birth to a single joey (although twins occur on occasion). As with all marsupials, the young are born while at the embryonic stage, weighing only . However, they have relatively well-developed lips, forelimbs, and shoulders, as well as functioning respiratory, digestive, and urinary systems. The joey crawls into its mother's pouch to continue the rest of its development. Unlike most other marsupials, the koala does not clean her
Koala Brown and Bauer during their stay in New South Wales. Home, who in 1808 published his report in the journal "Philosophical Transactions of the Royal Society", gave the animal the scientific name "Didelphis coola". The first published image of the koala appeared in George Perry's (1810) natural history work "Arcana". Perry called it the "New Holland Sloth" on account of its perceived similarities to the Central and South American tree-living mammals of genus "Bradypus". His disdain for the koala, evident in his description of the animal, was typical of the prevailing early 19th-century British attitude about the primitiveness and oddity