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 Because "Phascolarctos" was published first, according to the International Code of Zoological Nomenclature, it has priority as the official name of the genus. French naturalist Anselme Gaëtan Desmarest proposed the name "Phascolartos fuscus" in 1820, suggesting that the brown-coloured versions were a different species than the grey ones. Other names suggested by European authors included "Marodactylus cinereus" by Goldfuss in 1820, "P. flindersii" by René Primevère Lesson in 1827, and "P. koala" by John Edward Gray in 1827. The koala is classified with wombats (family Vombatidae) and several extinct families (including marsupial tapirs, marsupial lions and giant wombats) in the