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
Riversleigh rainforest koala Riversleigh rainforest koala codice_1 The Riversleigh rainforest koala (Nimiokoala greystanesi) is an extinct marsupial, closely related to the extant koala, that inhabited northwestern Queensland in the early-middle Miocene (23–16 million years ago). Along with species of sister genus "Litokoala", the Riversleigh rainforest koala is the smallest representative of family "Phascolarctide". Based on cladistic analysis, "Nimiokoala" is one of the more basal genera of "Phascolarctide". It died out due to climate change rendering the environment more arid. It probably had a more generalized diet than that of the modern species, but its exact food preferences are unknown. The generic name, "Nimiokoala,"