Koalas are endangered primarily due to habitat destruction, climate change, and diseases like chlamydia. koalas were listed as Vulnerable on the IUCN Red List. Precise population numbers are hard to estimate due to the koala's wide distribution across Australia, but some estimates suggest there may be as few as 43,000 to as many as 100,000 koalas left in the wild. Koalas are endangered primarily due to habitat destruction, climate change, and diseases like chlamydia.