Koalas nearly went extinct before humans arrived, DNA study reveals

A major DNA study has rewritten the koala's evolutionary story, revealing that the species suffered a dramatic population collapse about 100,000 years ago, long before humans arrived in Australia. By calculating the koala's mutation rate for the first time and analyzing hundreds of genomes, researchers discovered that every living koala traces back to a small group that survived extreme climate shifts and later repopulated eastern Australia.