Koala Research
Home of the Koala Ecology Group
The University of Queensland
St Lucia, Australia 4072

Koala Ecology Group

Koala Facts 1
Scientific name:  Phascolarctos cinereus
Conservation Status:  Vulnerable under Commonwealth and Qld State legislation.
Distribution:  Patchy in Eastern Australia
FOOD AND SHELTER: Koalas in Queensland eat a range of eucalypt species,
and also some small amounts of other genera, including Lophostemon and
Melaleuca. In some areas their favourite trees to rest in are not
species that they eat. In south east Queensland, koalas love to eat
Eucalyptus tereticornis, E. microcorys, E. robusta and several other
eucalypts. In central Queensland they eat coolibahs and poplar box, but
will also eat ironbarks and E. camaldulensis - depending on the

LIFE EXPECTANCY: Koalas can live to 20 years in captivity - but females rarely reach 15 years in the wild, and males are only occasionally found to reach ten years. The oldest koala in our study lived on St Bees island. She was over four kg when we caught her in 1999, and was still patrolling the same range in September 2014.

Koala Facts 2


Koalas are seasonal breeders, with peak births occurring in
November and December. The gender ratio in most populations is 1:1, but whereas 50% of all adult females can be expected to raise a young each year, only about a quarter of all adult males will produce young in any season. Did you know that female koalas tend to breed with a different male each year?

Home Ranges

Koalas in central Queensland can have home ranges of up to 100 hectares - but their cousins in south east Queensland can live in ranges as small as 2.4 hectares. Koalas seem to occupy ranges around 6 Ha in coastal
areas (based on our St Bees results).


The south east Queensland populations have been found to be genetically distinct from other populations and have suffered a 64% decline in numbers in the last ten years. Cars, dogs and disease are their biggest threats, with increasing urbanisation meaning that much of their formerhabitat is now gone, and their future is in doubt.


The most serious pathogen effecting koalas is the bacteria Chlamydia, two strains of which are known to infect koalas, leading to infertility, blindness and a host of other infections that reduce the chances of survival of individual koalas. The koala is also host to retrovirus - which is thought to be implicated in cancers such as lymphoma that can affect koalas.