Koala

The koala (Phascolarctos cinereus) is an arboreal marsupial of eastern Australia that feeds almost exclusively on eucalyptus leaves. It is listed as Vulnerable by the IUCN, and Australia classified populations in Queensland, New South Wales and the Australian Capital Territory as Endangered in 2022.

🧬 Field Guide Specimen: Open Koala in the CRV Science Field Guide to log the specimen, see its place among the Mammals lineages in the Cladogram Explorer, and test your recall in the Red List conservation game.

Eucalyptus leaves are poor in protein and contain toxins. Koalas have a long cecum full of microbes, a slow metabolism and sleep up to about 20 hours a day to save energy. Their liver detoxifies plant compounds that would poison most animals.

Chlamydia infections cause blindness and infertility, and koalas are also unusual in having a retrovirus, KoRV, in the process of becoming part of their genome. Habitat loss, vehicles and dogs take a toll, and the 2019 to 2020 bushfires killed or displaced many thousands. See Retroviruses.

The pouch opens toward the rear, and the joey drinks milk there for about six months. Koala fingerprints are strikingly similar to human ones, an example of convergent evolution of friction ridges.

• Retroviruses — endogenous retrovirus in koalas
• Wildfire — bushfire impact on habitat