What is a koala?

The koala is a tree-dwelling marsupial that feeds almost exclusively on the leaves of eucalyptus trees. Despite its common nickname of koala bear, it is not a bear. Koalas live in the eucalyptus forests of eastern and south-eastern Australia, including parts of Queensland, New South Wales, Victoria, and south-eastern South Australia.

Adult koalas weigh between 4 and 15 kilograms and have a thick grey or brown coat, large fluffy ears, and a black leathery nose. They sleep up to 22 hours a day, conserving energy because eucalyptus leaves are low in nutrients and contain compounds toxic to most other mammals. A koala's specialised digestive system, including a long caecum, breaks down these compounds. Koalas can recognise more than 600 species of eucalyptus but typically eat only a handful that grow in their home range.

Female koalas give birth to a single joey after a 35-day gestation. The joey spends about six months in the pouch, then rides on its mother's back for another six months while it learns to find suitable leaves. Mothers feed young joeys a substance called pap, a specialised faecal product that transfers gut microbes needed to digest eucalyptus.

Koalas have been listed as endangered in New South Wales, Queensland, and the ACT since February 2022, after being listed as vulnerable in 2012. Threats include habitat clearing, vehicle strikes, dog attacks, chlamydia disease, and bushfires. The 2019 to 2020 Black Summer bushfires killed an estimated 60,000 to 80,000 koalas. The federal government's Koala Recovery Strategy, released in 2024, aims to reverse the decline by protecting habitat corridors and managing disease.