No one does it quite like the koala when it comes to catching Z's. This adorable marsupial holds the record for the most sleep, dozing off for 18 to 22 hours a day. But why do koalas sleep so much? The primary reason koalas sleep so much lies in their diet. Koalas feed almost exclusively on eucalyptus leaves, which are low in nutrients and high in fibrous material and toxic compounds. This diet...