Koalas, distinctive marsupials native to Australia, are known for their arboreal lifestyle and reliance on eucalyptus leaves for sustenance and hydration. They spend most of their lives in trees, descending only to move between them or find new food. Despite their tranquil nature, koalas face various threats to their survival.
Natural Animal Predators
Wild animals do prey on koalas, though their overall impact on populations is not currently significant. Dingoes prey on adult koalas, especially when these marsupials are on the ground moving between trees. Large pythons also pose a threat to koalas on the ground or in lower tree branches.
Young koalas, known as joeys, are more vulnerable. Large birds of prey, such as wedge-tailed eagles and powerful owls, hunt joeys directly from trees. Goannas, a type of large lizard, also threaten young koalas. Feral foxes have been observed preying on young koalas when the mother descends to the ground.
Threats from Domestic Animals
Domestic animals, primarily dogs, present a significant danger to koalas, particularly where human settlements overlap with koala habitats. Dog attacks are a leading cause of koala mortality, ranking as the third most common cause of death after habitat clearing and vehicle collisions. These encounters often occur in residential backyards, especially at night when koalas are active on the ground.
A single dog bite can inflict severe internal injuries, even if external wounds appear minor, leading to high mortality rates. Studies indicate that over 70% of koalas subjected to dog attacks may die or require euthanasia. Feral cats also pose a threat to young koala joeys, as these agile predators can climb trees and target small, defenseless individuals.
Other Significant Koala Dangers
Koalas face numerous other dangers that impact their populations. Habitat loss and fragmentation are the most significant threat, driven by urban development, agriculture, mining, and infrastructure expansion. This destruction removes their food sources and shelter, forcing koalas to traverse dangerous ground.
Vehicle collisions are another frequent cause of injury and death for koalas, especially as they cross roads in fragmented landscapes. An average of almost 300 koalas are killed annually by motor vehicles in Southeast Queensland alone.
Diseases also undermine koala health, with Chlamydia being particularly widespread and debilitating. This bacterial infection can affect up to 100% of some koala populations, causing blindness, infertility, and urinary tract infections, which can ultimately be fatal. Stress from habitat degradation can exacerbate Chlamydia’s effects.
Bushfires represent a major threat, directly causing mortality, injuries, and extensive habitat destruction. The 2019-2020 bushfire crisis impacted an estimated 60,000 to 61,000 koalas across Australia.
Climate change further compounds these issues by increasing the frequency and intensity of heatwaves, leading to heat stress and dehydration in koalas. Rising temperatures and altered rainfall patterns also reduce the water content and nutritional quality of eucalyptus leaves, forcing koalas to descend to the ground in search of water, which exposes them to additional risks like vehicle collisions and dog attacks.