Why Koalas Sleep So Much

Koalas are famous for sleeping up to 20 hours a day. The reason is their diet. They eat eucalyptus leaves, which are tough, fibrous, and—to almost every other animal—toxic. Koalas have a specialized digestive system with a long cecum that slowly breaks down the leaves, but the process is incredibly energy-intensive. Their low-energy diet simply doesn’t provide the fuel for high activity. Sleeping is the koala’s way of conserving energy while it slowly digests its food. They aren’t lazy; they are perfectly adapted to a niche that few other animals can exploit, turning a toxic food source into a survival strategy.