Zurich, Switzerland – A male koala at Zurich Zoo rests in the fork of a large eucalyptus tree, using a strategy that helps the species cope with high temperatures.

The koala remains in an energy-saving position for hours, only occasionally moving, looking up, shifting position, and returning to rest. In the nearby area, a mother and daughter koala also spend their time sleeping in a tree.

Koalas use eucalyptus forests as natural air conditioners in their native habitat across Australia’s south and east coasts. They seek out cooler areas within forests and limit activity to cooler morning and evening hours.

Every movement creates body heat and uses energy, which is limited because eucalyptus is difficult to digest. As a result, koalas rest and sleep for up to 20 hours a day.

Koalas are also highly efficient water savers. They rarely drink because they receive most of their water from eucalyptus leaves, which contain 60 to 80 percent water. Their bodies extract moisture during digestion.

Heat waves above 35 degrees Celsius and drought periods can push koalas beyond their limits. The species is considered threatened, with estimates suggesting only about 400,000 to 570,000 animals remain in the wild.

Zurich Zoo contributes to securing a reserve population outside their natural habitat through keeping and breeding koalas and supports Koala Conservation Australia, which operates a koala hospital, works to preserve habitat, maintains research collaborations, and has established a breeding program for reintroduction.

Podcast: Play in new window | Download