Despite the common title ‘koala bear’, koalas are actually marsupials and not bears. The word koala comes from an aboriginal word that means ‘does not drink’. Although there is just one species koalas found in the southern parts of Australia are considerably larger and have thicker fur than those in the north. It is thought this is an adaptation to keep them warm in the colder southern winters. They are mostly nocturnal, sleeping for up to 18 to 20 hours a day to conserve energy.
There are over 600 varieties of eucalyptus, also known as gum trees, but koalas are fussy eaters and have strong preferences for different types of gum leaves. These leaves do not have a high nutritional value and are toxic to most other animals. They also take a long time to digest, which is partly why koalas spend so much time sleeping.
Koalas communicate with each other by making a range of noises, including a sound like a loud snore and a belch. Koala young are known as joeys. The joey stays in its mother’s pouch for about 6 or 7 months drinking only milk. Before it can tolerate gum leaves, the joey must feed on a substance called pap, which is a soft and runny form of the mother’s droppings. This allows the mother to pass on to the joey special micro-organisms from her intestine which are necessary for it to be able to digest the eucalyptus leaves.