Koala (Phascolarctos cinereus)
MammalMarsupialFolivore
Koala (Phascolarctos cinereus) in eucalyptus habitat.
Image: Bernard DUPONT, CC BY-SA 2.0, via Wikimedia Commons.
Overview
The koala (Phascolarctos cinereus) is an arboreal marsupial endemic to Australia. Despite the common nickname "koala bear", koalas are not bears at all — they are marsupials, more closely related to wombats than to any bear. Koalas are notable for a highly specialised diet consisting almost entirely of eucalyptus leaves and for a low-energy lifestyle marked by long periods of rest in trees.
Habitat & Range
Koalas inhabit eucalypt forests, woodlands, and coastal mallee habitats across parts of eastern and southeastern Australia. Habitat distribution depends on the presence of specific preferred eucalyptus species, which varies regionally. Some local populations have been the subject of significant range contraction over recent decades.
Diet
Koalas are eucalyptus-leaf specialists. Their digestive system is adapted to process the relatively low-nutrient, toxic-compound-rich leaves of various Eucalyptus species. Koalas typically eat large daily amounts of leaves and obtain most of their water from the leaves themselves, though they will also drink free water when necessary, particularly during drought.
Behavior
Koalas are almost entirely arboreal, descending to the ground primarily to move between trees. They spend a very large fraction of each day resting and feeding. Adult koalas are largely solitary and maintain overlapping home ranges. Mothers carry their developing joey in the pouch and then on the back after the joey is too large for the pouch.
Human Interaction & Conservation
Koala populations face significant pressures from habitat loss and fragmentation, vehicle strikes, dog attacks, chlamydial and other disease outbreaks, and large-scale fires — including the 2019–2020 Australian bushfires, which had severe impacts on populations in eastern Australia. Some populations are now listed under stronger protective categories than they were previously. Verify current status at iucnredlist.org and Australian conservation sources before publication.
Appearance & Recognition
Koalas have a compact, round-bodied shape with no visible tail, large rounded ears tufted with white fur, and a broad dark spoon-shaped nose set against pale ash-grey to light-brown fur. The chest and inner limbs are typically paler — often white — with a small variable patch of light fur on the rump in some southern populations. Body size and coat thickness vary regionally: koalas from cooler southern Australian populations tend to be larger and woollier than their northern counterparts.
A closer look at the forepaws shows a distinctive grip — two opposable "thumbs" alongside three fingers — that combines with strong hooked claws to provide a climbing hold on smooth eucalyptus trunks. The typical viewing posture, wedged into a tree fork high in a eucalypt, is itself a useful field cue. Despite the common nickname "koala bear", koalas are marsupials (with a forward-opening pouch in adult females) and are not related to bears at all — their nearest living relatives are wombats.
Similar Animals
The koala's closest living relatives are wombats, also marsupials. Together they form the order Diprotodontia, which also includes kangaroos, possums, and a number of other Australian and surrounding-region species.
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More photos of the koala
Koala with a joey on her back.
Image: Benjamint444, CC BY-SA 3.0, via Wikimedia Commons.
Wild koala (Phascolarctos cinereus) in Australian eucalyptus habitat.
Image: The Central Intelligence Agency, Public domain, via Wikimedia Commons.
Sourced facts
Each value below is traced to the specific reference that states it, listed at the end of this section. Reviewed 2026-09-22.
| Fact | What the source states | Source |
|---|---|---|
| Body size | In the south, males average about 78 cm and females about 72 cm head and bodySouthern animals only; the account gives no equivalent northern measurement. | Animal Diversity Web |
| Weight | Southern animals: males about 11.8 kg, females about 7.9 kg. Northern animals: males about 6.5 kg, females about 5.1 kgMass differs by region and sex by roughly a factor of two, so a single figure would be wrong for most animals. | Animal Diversity Web |
| Lifespan | May live past 10 years in the wild; about 15–20 years in captivitysources disagreeThe account states koalas may live past 10 years in the wild while also citing a wild average of 17 years, which cannot both be typical. Both are reproduced. | Animal Diversity Web |
| Geographic range | Eastern Australia, from northern Queensland to south-western Victoria | Animal Diversity Web |
| Habitat | Arboreal in eucalyptus forest below about 600 m | Animal Diversity Web |
| Diet | Herbivorous, feeding on eucalypt and some non-eucalypt foliage; an adult can eat about 500 g a day | Animal Diversity Web |
| Activity pattern | Mainly nocturnal, sleeping up to 18 hours a day | Animal Diversity Web |
| Social structure | Primarily solitary, though sometimes in small groups led by a single male | Animal Diversity Web |
References for the facts above
- UniversityAnimal Diversity Web — University of Michigan Museum of ZoologySupports: Body size, mass, lifespan, geographic range, habitat, diet, activity pattern and social structure. Retrieved 2026-09-22.Limitations: A peer-edited account written largely by students under faculty review. Figures are compiled from the literature rather than from a single study, and some are regional.