Koala
The koala is one of Australia’s most recognizable marsupials, famous for its round, fluffy ears, large black nose, and sleepy demeanor. Often called the “koala bear,” it is not a bear at all but a tree-dwelling marsupial closely related to wombats. These animals are highly specialized for a life spent almost entirely in eucalyptus trees, where they eat, sleep, and socialize.
Meet the Koala
Classification
Koalas are medium-sized marsupials, with adults measuring between 60 to 85 centimeters (24 to 33 inches) in length and weighing between 4 to 15 kilograms (9 to 33 pounds). Their thick, woolly fur varies in color from light gray to brown, with a cream-colored underside.
Southern koalas tend to be larger and have denser fur than their northern counterparts, an adaptation to the colder climate. Their large, fluffy ears provide excellent hearing, while their leathery nose is highly sensitive to scent.
Koalas are uniquely adapted for their arboreal lifestyle. Their hands have two opposable digits, which help them grip tree branches securely. Their sharp claws and rough paw pads provide additional traction on tree bark. Unlike most marsupials, koalas have a relatively short tail, which offers little support in climbing but helps with balance. Their digestive system is also highly specialized, with an enlarged cecum that allows them to break down toxic compounds found in eucalyptus leaves.
Where Does the Koala Live?
Biogeographic Realm: Australasia
Continents: Oceania
Subcontinents: Australia and New Zealand
Countries: Australia
Koalas are native to eastern and southeastern Australia, inhabiting eucalyptus forests and woodlands in Queensland, New South Wales, Victoria, and South Australia. Their distribution is directly tied to the availability of specific eucalyptus species, as they rely on these trees both for food and shelter. Different populations of koalas have adapted to various climates, from warm, humid coastal forests to cooler, dry inland regions.
Their habitat is structured around home ranges, with dominant males occupying larger territories that overlap with several females. They prefer areas with high-quality food trees and minimal human disturbance. However, habitat fragmentation due to deforestation, urban expansion, and climate change has significantly impacted koala populations in recent years.
What Do Koalas Eat?
Koalas are strict folivores, feeding almost exclusively on eucalyptus leaves. Out of the hundreds of eucalyptus species available, they prefer only a select few, carefully choosing leaves based on their nutrient content and low toxin levels. An adult koala consumes about 500 grams (1.1 pounds) of leaves per day, using their sharp molars to grind the tough foliage into a digestible pulp.
Their slow metabolism helps them process their fibrous diet, extracting as much energy as possible from the nutrient-poor leaves. To further aid digestion, koalas have a specialized gut microbiome that breaks down the tough cellulose and detoxifies the harmful compounds found in eucalyptus. Because eucalyptus leaves contain a high percentage of water, koalas rarely need to drink, obtaining most of their hydration from their food.
What Eats Koalas? – Predators & Natural Enemies
Adult koalas have few natural predators due to their arboreal lifestyle, but they are not entirely safe from danger. Large birds of prey, such as powerful owls and wedge-tailed eagles, sometimes target juvenile koalas. On the ground, dingoes, large pythons, and domestic dogs pose a significant threat, especially when koalas descend from trees to move between feeding sites.
Young koalas, or joeys, are particularly vulnerable. Goannas (large monitor lizards) are known to raid tree hollows, preying on baby koalas left unattended. Additionally, after death, their carcasses provide food for scavengers such as foxes and ravens. While predation is a natural threat, habitat loss and disease pose far greater risks to koala populations today.
Behavior & Lifestyle
Koalas are primarily nocturnal and crepuscular, being most active during the night and early morning hours. They spend most of their time resting in eucalyptus trees, sleeping for up to 20 hours a day. This excessive sleep helps them conserve energy, as their diet provides little in the way of quick-burning fuel. During cooler weather, they may be more active during the day, particularly in shaded areas.
Socially, koalas are largely solitary but maintain loose social structures within overlapping home ranges. Males establish dominance through deep, resonating bellows that can be heard over long distances, deterring rival males and attracting potential mates. They also use scent marking, rubbing their chest glands against tree trunks to claim territory.
Koalas are expert climbers, using their strong limbs and sharp claws to move between branches with ease. While they are agile in the trees, their movement on the ground is slow and clumsy, making them more vulnerable to predators. When moving between trees, they prefer to use connected branches but will descend to the ground if necessary.
How Do Koalas Reproduce?
Koalas have a breeding season that typically runs from September to March. Males compete for mates through vocal displays and physical confrontations. Once a female chooses a mate, gestation lasts about 35 days, after which a single joey is born. The tiny, underdeveloped newborn, weighing less than a gram, crawls into its mother’s pouch, where it continues to develop for six to seven months.
Once the joey emerges from the pouch, it clings to its mother’s back for additional support and protection. During this stage, it begins eating a special, semi-digested form of feces called “pap,” which helps introduce necessary gut bacteria to process eucalyptus leaves. By around 12 months old, the joey is fully weaned and ready to establish its own territory.
Are Koalas Endangered? – Conservation Status & Threats
The International Union for Conservation of Nature (IUCN) lists the koala as a “vulnerable” species, but some regional populations are considered endangered. Habitat destruction due to land clearing, agriculture, and urban development is the greatest threat to koalas, as it leads to population fragmentation and food scarcity. Bushfires, exacerbated by climate change, have also decimated koala habitats in recent years.
In addition to habitat loss, koalas face significant health challenges. Chlamydia, a bacterial infection, has become widespread in many populations, causing blindness, infertility, and severe urinary tract infections. The koala retrovirus (KoRV) further weakens their immune systems, making them more susceptible to other diseases.
Conservation efforts include habitat restoration projects, wildlife corridors to connect fragmented populations, and medical treatment programs for diseased koalas. Organizations such as the Australian Koala Foundation continue to advocate for stronger protections and conservation measures to ensure the survival of this beloved species.
