A group of koalas at Longleat Safari Park in Wiltshire have helped discover a potential scientific breakthrough in research to save the species in the wild.
Scientists working with the animals have made a genetic breakthrough which could help secure the long-term survival of the marsupial.
A kidney disease known as oxalate nephrosis is common among koalas and one of Longleat's own animals, Wilpena, died of the condition.
From the new research, scientists believe they have worked out the exact genetic mutation that causes that kidney disease.
The koala is considered "threatened" by the International Union for Conservation of Nature - a result of disease and habitat loss.
As things stand, the species is likely to become endangered unless urgent action is taken to reverse the decline in numbers.
It's estimated that Australia's 100,000 remaining koalas are suffering from a series of illnesses caused by a limited genetic diversity.
Researchers from the University of Nottingham’s School of Veterinary Medicine and Science worked with Longleat koalas and their keepers to identify a genetic mutation that could help protect the animal against disease.
Koalas are most at risk of kidney disease, cancers, and a form of HIV.
Lead researcher on the study, Dr Rachael Tarlinton, is Associate Professor of Veterinary Virology.
The team have been able to design tests which "could have taken years" to develop without the data collected from Wilpena.
Longlet Head Keeper Graeme Dick said the breakthrough could be "a real game-changer".
Researchers say the koala population's genetic problems can be traced back to mass culls in the 19th and 20th centuries.
An estimated eight million of the animals were killed.