A critically endangered possum has been born in captivity for the first time in more than 20 years, renewing hopes the species' dwindling population can eventually return to the wild.
Two highland Leadbeater's possums were born at Victoria's Healesville Sanctuary after zookeepers changed the nocturnal marsupials' diet.
Experts loaded their honey-based nectar with more fibre and vitamins, which boosted the possums' microbiome and reproductive health, and increased sperm production in males.
"This breeding success with highlands Leadbeater's possums has shown us that the dietary and husbandry changes we have made are working," Zoos Victoria manager Monika Zabinskas said in a statement.
"It gives us hope that we could breed lowland Leadbeater's in the future."
Only a few thousand of the highland population and fewer than 30 of the lowland species remain in the wild.
"It highlights that if worse comes to worse in the wild, captive breeding could become a potential mechanism to help the species," University of Melbourne Associate Professor Craig Nitschke told AAP.
"It's a wonderful achievement, but it doesn't replace the need for conserving its native habitat. That's by far the most important thing."
The Leadbeater's possum was successfully bred in captivity in the 1990s but the program ended due to ageing animals and limited genetics.
The program restarted in 2012, with keepers spending the past 10 years closely reviewing husbandry practices and the possum's complex dietary needs.
There's hope the positive changes to the breeding program could benefit the lowland Leadbeater possum species.
"If they can get the highland genes into the lowland population to bolster the population, that would be absolutely critical," Prof Nitschke said.
"If this is a step towards that, then it's fantastic."
The Leadbeater's possum is one of two Victorian faunal emblems and the state government is contributing $2 million to help the long-term sustainability of the endangered species.