Koalas are marsupials, which are animals that carry their young in a pouch. They are found in Australia. Koalas feed exclusively on the leaves of eucalyptus trees and become so saturated with the essential oils of this plant that they smell just like cough drops. Eucalyptus leaves are very low in nutrients and protein and are very slow to digest, so koalas rest for about 20 hours of the day to conserve energy.