HomeScienceKangaroo Island Koalas face hidden genetic threats despite abundance

Kangaroo Island Koalas face hidden genetic threats despite abundance

Researchers compared Kangaroo Island koalas with those in Victoria and Queensland using whole-genome sequencing. They found much more inbreeding, which could make these animals less able to cope with future threats.

September 18, 2025 / 17:54 IST
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Kangaroo Island koalas show longer and more frequent stretches of identical DNA inherited from both parents. Scientists call these runs of homozygosity, a clear marker of inbreeding. (Image: Flinders University)
Kangaroo Island koalas show longer and more frequent stretches of identical DNA inherited from both parents. Scientists call these runs of homozygosity, a clear marker of inbreeding. (Image: Flinders University)

At first glance, Kangaroo Island in South Australia looks like a koala sanctuary. The island holds a large, disease-free population, often seen as a conservation success story. But is this picture really so simple?

Why Are Scientists Concerned About Koalas Here?
New research from Flinders University has revealed a worrying legacy. Although the population is abundant, its genetic diversity is far lower than mainland groups. Researchers compared Kangaroo Island koalas with those in Victoria and Queensland using whole-genome sequencing. They found much more inbreeding, which could make these animals less able to cope with future threats.

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How Did This Problem Begin?
The history goes back to the 1920s. Fewer than two dozen koalas were moved from Victoria to Kangaroo Island to save them from hunting and habitat destruction. But those animals already came from a small and genetically limited group. Today, east coast koalas are endangered, struggling with habitat loss, bushfires, road expansion and disease. In contrast, Kangaroo Island koalas grew in number, even after bushfires destroyed more than half of the island in 2019–20.

(Image: Flinders University)