Take a cue from today"s image; this sleepy koala may inspire you to catch some Z"s. These adorable Australian marsupials can sleep up to 20 hours a day, which helps them conserve the little energy they get from their eucalyptus-based diet. Koalas have specialised digestive systems adapted to detoxify the chemicals present in eucalyptus leaves, which are toxic to many other animals. Koalas move slowly when awake, spend most of their time tucked into nooks in trees and have a lower body temperature than other animals of their size.