The Question: Which Australian mammal spends most of its life in trees?
Koalas spend almost all their lives in eucalyptus trees, whose fragrant leaves provide them with all the food they need. They touch ground occasionally, usually to move to another tree.
Because eucalyptus leaves are low in calories and nutrients, koalas conserve energy by resting and sleeping up to 20 hours a day (in the branches of trees, of course). They spend their waking hours feeding. Eucalyptus leaves are poisonous to most animals, but the digestive systems of koalas are able to detoxify them.
The correct answer is Koala.