Koala

Koala facts at a glance

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A specialized leaf diet

Koalas eat almost nothing but eucalyptus leaves, which are tough, low in nutrients, and toxic to most animals. A special digestive system lets koalas break down these leaves and neutralize the toxins. Because the diet provides so little energy, koalas sleep up to 20 hours a day to conserve it.

Life in the trees

Koalas are superbly adapted to life in the canopy, with strong limbs, rough paw pads, and two opposable thumbs on each front paw for gripping branches. They rarely come down to the ground, where they are slow and vulnerable, and they get most of their water from the moisture in leaves.

Raising a joey

Like other marsupials, koalas give birth to a tiny, undeveloped joey that crawls into the mother's pouch to keep growing. After about six months it begins riding on her back. Young koalas eat a special form of their mother's droppings to gain the gut microbes needed to digest eucalyptus.

Conservation

Koalas are listed as Vulnerable, and populations in parts of eastern Australia are declining sharply. Habitat loss, bushfires, disease, vehicle strikes, and dog attacks are the main threats, and protecting and replanting eucalyptus forest is central to their recovery.

Did you know? Koala facts

• Koalas are marsupials, not bears, and carry their young in a pouch.
• They eat eucalyptus leaves that are toxic to most animals.
• Koalas sleep up to 18–22 hours a day to conserve energy from a low-nutrient diet.
• Each koala has unique fingerprints, remarkably similar to a human's.
• Joeys eat their mother's 'pap' to gain the gut microbes needed to digest eucalyptus.
• Habitat loss, disease, and bushfires have made koalas endangered in parts of Australia.

Diet & feeding

Koalas feed almost exclusively on eucalyptus leaves, selecting particular species and even individual trees, and obtain most of their water from foliage.

Adaptations

• A specialised gut and liver detoxify eucalyptus compounds poisonous to other animals. (Nowak 1999)
• An enlarged caecum ferments tough, fibrous leaves to release scarce nutrients.
• Sharp claws and opposable digits grip and climb smooth eucalyptus trunks.
• A very low metabolic rate and long sleep conserve energy on a poor diet.

Behaviour & ecology

• Koalas are solitary and largely nocturnal, spending most of their time in trees.
• Individuals occupy overlapping home ranges centred on favoured food trees.
• Males bellow loudly to advertise presence during the breeding season.
• Joeys ride on the mother's back after leaving the pouch.

Communication

• Males produce a deep, resonant bellow far lower than expected for their size.
• Scent-marking from a chest gland advertises territory and status.
• Vocal squeaks and screams feature in distress and disputes.

Habitat & range

Koalas live in eucalyptus woodlands and forests of eastern and southeastern Australia, depending entirely on the presence of suitable food trees.

Ecological role

As specialist eucalyptus folivores, koalas are an iconic indicator species whose decline reflects the loss and fragmentation of Australian woodland.

Conservation status of the Koala

Sources & references

This guide is compiled and reviewed against established zoological and conservation references. Key sources for the Koala:

• IUCN Red List of Threatened Species

  Conservation status (Vulnerable) reflects the IUCN Red List category for Phascolarctos cinereus, most recently assessed in 2014.

• Woinarski, J. & Burbidge, A. A. (2020). Phascolarctos cinereus. IUCN Red List of Threatened Species.

  Status (Vulnerable) and threats.

• Animal Diversity Web — Phascolarctos cinereus. University of Michigan Museum of Zoology.

  Life history, morphology, and range.

• Nowak, R. M. (1999). Walker's Mammals of the World (6th ed.). Johns Hopkins University Press.

  Physiology and diet.

• Global Animal Guide editorial standards

  How we research, source, review, and update every guide for accuracy.