Koalas are marsupials native to Australia and are the primary eucalyptus eaters. They have a diet that consists almost entirely of eucalyptus leaves, which provide them with the necessary nutrients and water. Koalas have a special digestive system that allows them to digest the tough eucalyptus leaves. They also have a unique set of teeth that are adapted to grinding the leaves. Koalas are an iconic species in Australia and are beloved by many people around the world.