DNA Study Finds Koalas Collapsed 100,000 Years Ago Before 65,000-Year Human Arrival
Updated
Updated · ScienceDaily · Jul 19
DNA Study Finds Koalas Collapsed 100,000 Years Ago Before 65,000-Year Human Arrival
3 articles · Updated · ScienceDaily · Jul 19
Summary
A genomic analysis of 457 koalas found the species began a major population decline about 100,000 years ago, with a severe genetic bottleneck nearly 60,000 years ago—well before humans reached Australia.
Four parent-offspring trios let researchers calculate koalas' mutation rate directly for the first time, about half the human rate, replacing older estimates borrowed from distant mammals.
The timing points to late-Pleistocene climate upheaval—glacial drying, fire-prone landscapes and habitat fragmentation—as the main driver; a surviving eastern population later repopulated the species.
Between 16,500 and 6,000 years ago, that remnant population split into five lineages that underpin today's east-coast koalas, while the western population disappeared.
The findings challenge earlier human-arrival theories and could sharpen conservation planning as Queensland and New South Wales populations still decline, even as Victoria shows recovery.
A study shows koalas collapsed from past climate change. Why do some now call them a low-risk species for future heat?
Koalas survived a prehistoric ice age. Why are modern, human-driven threats proving more deadly?
From Ancient Collapse to Modern Crisis: The Genomic Story and Conservation Future of Australia’s Endangered Koalas
Overview
Koalas in Queensland, New South Wales, and the ACT are now listed as Endangered, reflecting a long history of decline and modern threats. Their populations are difficult to estimate, but researchers use advanced methods to track numbers. Today, koalas face severe challenges, mainly from habitat loss, fragmentation, and climate change, which make survival harder. Additional dangers like vehicle strikes and bushfires further threaten their existence. These combined pressures have led to urgent warnings that koalas could disappear from some regions by 2050 unless strong conservation actions are taken to protect their habitats and address these threats.