The rare images of the baby quolls at play were taken by wildlife photographer Charles Davis at Mulligans Flat, next to Forde in Gungahlin, in a shoot organised by the Woodlands and Wetlands Trust.

Belinda Wilson, a PhD candidate from the Australian National University, has been driving the project after the release of the first 16 Eastern Quolls into the sanctuary in 2016.

Ms Wilson said after the quolls becoming extinct on mainland Australia 50 years ago, there were now about 40 to 50 in the Mulligans Flat reserve.

With the removal of the threats of foxes and cats, due to innovative predator-proof fences, the Eastern Quoll has been given a fighting chance to re-establish itself once again.

Ms Wilson introduced Mr Davis to a den site she was monitoring for her research, and he quietly waited for them to emerge.

The result was images of the playful and boisterous pups enjoying some time outside the den.

"It's extremely rare to seem them like this," she said. "And we were quite surprised how calm they were around the photographer

Ms Wilson said the pups were probably three to four months old and within a matter of weeks would leave their mother, named Donna, for good, becoming solitary, night-time hunters.

"They need to learn how to hunt, how to creep up on prey, and what better way to practice than on your brother or sister," she said, adding that while they might also look like were attempting mating in some of the photographs, that was not the case. They were too young for that.

The carnivorous marsupial eats "anything smaller than it", according to Ms Wilson. Mice, reptiles, eggs, but mostly insects.

Ms Wilson said the quolls were thriving in the sanctuary, an insurance against total extinction of the animal, which was under threat in Tasmania where it existed in thr wild but was under threat from deforestation and climate change.

"Last year's release saw a staggering survival rate of 92 per cent, with at least 10 females (from that release and the year before) giving birth to up to 60 'quollets'. Through our most recent round of monitoring we caught over 40 animals, which is amazing given eastern quolls are so hard to catch," she said.

Visitors to Mulligans Flat can also take a twilight tour to try to see the quolls. Ms Wilson is also a guide on the tours.

"Each tour, I reckon there is about a 50-50 chance of seeing them because we've got so many now," she said.

"And they are the easiest to distinguish because they have the brightest eye shine of any of the animals there."

The Eastern Quoll reintroduction is a partnership between the ACT Government, the Australian National University (supported by the Australian Research Council), Mt Rothwell Conservation and Research Centre and the Woodlands and Wetlands Trust.