A tiny win for a species hanging on by a thread. Healesville Sanctuary in Victoria has successfully bred 12 critically endangered mountain pygmy possums, with fewer than 2,000 of the animals left in the wild.

The sanctuary said three mothers each produced litters of four offspring in its breeding program, the maximum number of young for the species.

The joeys were born last October. They spent four weeks in their mothers’ pouches before they were old enough to be left in nest boxes.

Mountain pygmy possums become fully independent at about three months old, but zookeepers have only now had their first in-person look at the joeys during their first vet checks at the sanctuary’s Australian Wildlife Health Centre.

Staff had been watching their movements on CCTV before then.

It is understood that fewer than 2,000 mountain pygmy possums remain in the wild, and Healesville Sanctuary said every single one is valuable.

Healesville Sanctuary Threatened Species Coordinator Nicole Boys said the joeys already resembled the adults.

“The best way to identify them is by their big heads and much littler bodies.”

She said the 12 young possums would stay at the sanctuary as part of the breeding program.

“These little joeys will remain here in our breeding programme, and hopefully, in the coming years, they will go on to breed, sharing their genes.”

The species is critically endangered because its alpine habitat is shrinking due to climate change. Its key food source, the Bogong Moth, has also significantly declined in recent years.

The animals also face habitat fragmentation and predation from cats and foxes.