Koalas are food specialists. They feed exclusively on the leaves and bark of eucalyptus trees. Usually, a koala uses no more than five to ten different eucalyptus trees in its territory. The animals are very choosy, because the leaves contain toxins, which the koala can tolerate to a certain extent. However, if it eats too much of it, even a koala can die from it. With their sense of smell they prefer to choose slightly younger or older leaves, depending on the species and the season. It is important that the leaves contain as few toxins as possible. Before the leaves are eaten, they are sniffed extensively and then chewed in their mouths for a long time until they are swallowed.
Many dangers lurk for koalas: Natural enemies are dingoes, eagles, monitor lizards and pythons. Stray dogs, swimming pools and cars are also major hazards. Furthermore, long dry seasons, bush fires and construction projects can have dramatic consequences. If a road is built through its territory, the koala will remain on this side of the road on which it was when the road was built. He will hardly ever cross the road again. The part of the territory on the other side of the road is lost for him.
|Related to||Marsupials (320 species), koala (3 subspecies)|
|Habitat||Sparse eucalyptus forests|
|Mode of life||Arboreal, for locomotion rarely also on the ground, nocturnal, sleep up to 20 hours per day|
|Social structure||Solitary, but in overlapping territories|
|Diet||Daily 400 to 600 g of leaves and bark of 5 to 10 different eucalyptus species, rarely fruits of eucalyptus trees|
|Weight||Females 6 to 11 kg, males 8 to 12 kg (animals in the colder south are usually larger), newborns less than 1 g|
|Head-torso length||61 - 85 cm|
|Tail length||1 - 2 cm|
|Mating season||October till April|
|Gestation time||35 days, then at least 160 days in the pouch|
|Litter size||1 young|
|Age of sexual maturity||2 - 3 years|
|Life expectancy||Females 15 years (in zoos up to 19 years), males 10 years|
|Utilization||Formerly fur, cultural symbol in Australia (politics, sports, science)|
|Population trend||45,000 to 80,000 animals, reintroduced in some regions and on islands, extirpated in some regions, sometimes considered pests|
|At Zurich Zoo since||2018, internationally coordinated breeding (EEP)|
Arrival of the koalas at Zurich Zoo.
Koala checks eucalyptus leaves. (Photo from the Australian Reptile Park.)
Koala eating eucalyptus leaves (Photo taken at Australian Reptile Park.)
|UKI||A. Fausch-Gasner, Fanas|
|UKI||A. Baleri, Uetikon am See|