Koalas are one of Australia’s most iconic animals, instantly recognizable by their fluffy ears, large noses, and sleepy expressions. One of the most well-known facts about koalas is how much they sleep—up to 18 to 22 hours a day. But why do these adorable marsupials spend so much time snoozing? The answer lies mainly in their diet, metabolism, and unique biology. A Diet Low in Energy Koalas survive almost entirely on eucalyptus leaves, which are low in nutritional value and difficult to digest. These leaves contain toxins that are harmful to most animals, but koalas have evolved a specialized digestive system to break them down. However, even with this adaptation, eucalyptus provides very little usable energy. Because of this, koalas need to conserve as much energy as possible. Sleeping for long hours helps them do just that. By reducing physical activity and staying still for most of the day, koalas avoid burning the limited energy they get from their food. Slow Metabolism K...