Freeze Koala Sperm to Save the Species From Extinction, Researchers Say

Scientists are working to find ways to save koalas, which have been devastated by droughts, deforestation, and bushfires.
koala sperm bank
Some 60,000 koalas were killed in 2019-2020 bushfires in Australia. Photo: Marius Becker / dpa / AFP

Having sperm banks for koalas could save the endangered species from being wiped out, Australian researchers say.

Research predicts the fluffy marsupials could be extinct by 2050 in parts of Australia due to droughts, deforestation, and bushfires. Between June 2019 and February 2020, some 60,000 koalas were killed or hurt during wildfires, according to the World Wildlife Fund. The Australian Koala Foundation estimates that there could be as few as 43,000 Koalas left in the wild.


But scientists at several Australia universities said freezing sex cells, like we do for people, could save the threatened species.

In a paper published in the international peer-reviewed journal Animals on Thursday, conservation scientist Ryan Witt, of the University of Newcastle, suggests that female koalas could be successfully impregnated with frozen sperm in a bred-for-release program.

Such a model would also cut breeding costs by five to 12 times by reducing the number of captive koalas needed. Current captive breeding programs require a much larger koala colony size to prevent inbreeding, and can cost more than $17,650 per animal annually. It’d also take little effort to integrate the model into practice, as 16 wildlife hospitals and zoos across Australia can act as koala sperm collecting branches, according to Lachlan Howell, the lead author of the paper.

Inbreeding too could be reduced, a problem which can adversely affect koalas’ health. “These issues can also compromise survival, disease resistance, and the species’ ability to adapt to changing environmental conditions from climate change,” Witt said in an article published by the University of Newcastle.

Using sperm banks to save endangered animals, though difficult, is a tried and true method. 

The black-footed ferret, one of the most endangered mammals in North America, was thought to be extinct until it was rediscovered in Wyoming in 1981. Though still endangered, it was brought back from near elimination using various assisted reproduction methods, such as captive breeding and sperm freezing. In 2008, two ferrets gave birth to kits that were spawned by sperm frozen a decade earlier. 

In July, scientists in Japan also successfully reproduced mice using freeze-dried sperm preserved in space for nearly six years.

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