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 spellings such as "coola" or "koolah"), it was changed to "oa", possibly in error. Because of the koala's supposed resemblance to a bear, it was often miscalled the koala bear, particularly by early settlers. The generic name, "Phascolarctos", is derived from the Greek words "phaskolos" "pouch" and "arktos" "bear". The specific name, "cinereus", is Latin for "ash coloured". The koala was given its generic name "Phascolarctos" in 1816 by French zoologist Henri Marie Ducrotay de Blainville, who would not give it a specific name until further review. In 1819, German zoologist Georg August Goldfuss gave it the binomial "Lipurus cinereus".