Mammals · Marsupials

Koala

Phascolarctos cinereus

Vulnerable

The koala is a tree-dwelling marsupial found only in eastern and southern Australia, built almost entirely around a single food source: eucalyptus leaves, which are toxic or unpalatable to nearly every other mammal. Slow-moving and largely solitary, it sleeps up to 20 hours a day to conserve the little energy its low-nutrition diet provides.

Classification

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia

Order: Diprotodontia

Family: Phascolarctidae

Genus: Phascolarctos

Species: cinereus

Nearest relative: Wombats — its only living relatives

Size

24–33 in. long; northern koalas are notably smaller than southern populations, an unusual reverse of the typical size-with-latitude rule.

Weight

9–33 lbs; southern Victorian koalas can be more than double the weight of Queensland koalas.

Habitat

Eucalyptus forest and woodland along the eastern and southern coasts of Australia.

Description

A stocky, tailless body, large fur-lined ears, a prominent black nose, and rough grey-brown fur that varies in thickness by climate.

Diet

Almost exclusively eucalyptus leaves — around 1 to 1.5 lbs a day from a narrow set of preferred species out of the roughly 700 eucalyptus species in Australia.

Digestion

An unusually long cecum, over 6 feet, hosts bacteria that break down eucalyptus toxins and extract what little nutrition the leaves contain.

Activity

Sleeps or rests 18–20 hours a day to conserve energy on a low-calorie diet; almost entirely nocturnal when active.

Communication

Males produce a deep, resonant bellow far louder than expected for their size, used to advertise size and location to rivals and females.

Gestation

About 33–35 days.

Birth & Joey Development

A single joey, the size of a jellybean at birth, lives in the pouch for about 6 months, then rides on its mother’s back for several more.

Sexually Mature

2–3 years for females, 3–4 years for males.

Life Span

13–18 years in the wild.

Did You Know?

Koalas are not bears — they are marsupials, and "koala bear" is a misnomer coined by early European settlers who thought the animal resembled a small bear.

Did You Know?

A koala's fingerprints are so similar to a human's that they have, in rare forensic cases, been mistaken for human prints at a crime scene.

Did You Know?

Eucalyptus leaves are so low in nutrition and so difficult to digest that koalas sleep up to 20 hours a day just to conserve the energy needed to process them.