Koalas are exclusively native to Australia, where they are one of the country’s most globally recognized animals. The koala is an arboreal herbivorous marsupial, not a bear, despite the common misnomer. Their presence is a defining characteristic of Australian wildlife, making them an iconic symbol of the continent’s biodiversity. They are the sole living representatives of the family Phascolarctidae; their closest relatives are the wombats.
Geographic Range Within Australia
The wild population of koalas is not distributed across the entire continent, but is instead concentrated in the eastern and southeastern coastal regions of mainland Australia. Their range extends from the Atherton Tableland in northern Queensland down through New South Wales and Victoria, reaching into South Australia. Koalas primarily inhabit the open eucalypt forests and woodlands that provide both shelter and their specific food source.
Populations are highly fragmented across this broad range, with varying degrees of health and abundance in each state. In Queensland and New South Wales, koalas are found most frequently along the central and northern coastal areas. Koalas in South Australia and Victoria are largely the result of successful reintroduction programs after populations were almost eliminated in the early 20th century. Due to these reintroduction efforts, koalas in the southern states tend to be physically larger and have thicker fur as an adaptation to the cooler climate.
The Koala’s Diet and Habitat
The koala’s diet consists almost entirely of Eucalyptus leaves. This foliage is low in nutritional value, high in fibrous material, and contains toxic chemical compounds poisonous to most other mammals. Koalas have evolved specialized adaptations, including a very long pouch in their intestine called a cecum. This cecum houses symbiotic bacteria that break down tough cellulose and detoxify the compounds.
This selective, low-energy diet dictates a sedentary lifestyle, requiring koalas to sleep for up to 20 hours daily to conserve energy. They consume between 200 to 500 grams of leaves daily. Koalas are highly selective, regularly eating from only about 30 of the over 600 available Eucalyptus species. Habitat quality is determined by the specific eucalypt species present, with koalas favoring trees that offer leaves with higher protein and moisture content.
Conservation Status and Population Threats
The conservation status of koalas varies significantly depending on the region, reflecting the fragmented nature of their populations. In February 2022, the Australian government listed the combined koala populations in Queensland, New South Wales, and the Australian Capital Territory as ‘Endangered’ under the national Environment Protection and Biodiversity Conservation Act (EPBC Act). This listing responded to dramatic population declines in the northern and central parts of their range.
Koala populations in Victoria and South Australia are currently considered stable and are not listed as threatened under the EPBC Act. The primary threats facing koalas are anthropogenic, with habitat loss and fragmentation from urbanization and land clearing being major factors. Severe bushfires, such as those experienced during the 2019–2020 season, have also caused loss of both koalas and their habitat. Other issues include road strikes, dog attacks, and the widespread prevalence of Chlamydia, a disease that can cause blindness, infertility, and death.