Koalas are herbivorous marsupials primarily consuming eucalyptus leaves, which they can efficiently digest despite their low nutritional value and toxins. They live exclusively in Australia, particularly in eucalyptus woodlands and are adapted to a sedentary lifestyle, spending much of their time sleeping and climbing trees to avoid predators. Koalas have unique reproductive traits, giving birth to underdeveloped young that stay in the mother's pouch for several months, and can live up to 18 years in captivity.