The primary food source of a koala is eucalyptus leaves. These Australian marsupials are highly specialized feeders, relying almost exclusively on eucalyptus for their nutrition. Koalas have a unique digestive system, which includes a specialized organ called a cecum, allowing them to break down the tough, fibrous leaves and extract the necessary nutrients. Eucalyptus leaves are low in protein and high in fiber, requiring koalas to consume large quantities to meet their energy needs. Their diet varies with the season, as koalas selectively choose specific eucalyptus species based on availability and their nutritional content. Conservation efforts focus on preserving eucalyptus habitats, vital for their survival.