But last month Sheva the snow leopard, who arrived at Canberra's National Zoo and Aquarium in 2002, passed away aged 19.

After arriving from Mogo Zoo, Sheva and her brother Bhutan quickly became crowd favourites with the zoo's visitors, despite being notoriously tricky to spot.

Snow leopards are listed as vulnerable with about 6000 left in the wild, but that number could be as low 3900, Ms Ness advised. Their elusive nature makes them difficult to study. There are about 10 left in captivity in Australia.

Senior carnivore keeper Katie Ness said in her five years of working with Sheva, she got to see two distinct sides to her, particularly after Bhutan passed away about 18 months ago.

"She was definitely the boss, she had it all over her brother," Ms Ness said.

"She didn't really seek out much attention from us."

But during the 18 months after her brother passed Sheva became very affectionate with her keepers.

"It was always on her own terms though," Ms Ness said.

"She was very independent."

Ms Ness said Sheva absolutely loved her food. She had a diet of various meats including chicken and deer but her favourite was rabbit.

She said at age 19 Sheva was considered very old for a snow leopard. The oldest ever snow leopard in captivity was 22 but in the wild Sheva may have lived only to about 10 years old.

She said she and the other zoo staff still missed Sheva everyday.

"It was incredibly sad, but in some ways it was almost a relief for her too," Ms Ness said.

"As much as we love our animals, we don't want to see them in pain.

"I know it was her time and that made it a little bit easier."

Sheva had become arthritic in her old age and there was some fear she would struggle to move around her enclosure which was designed to imitate the mountains of Central Asia - minus the snow - where they live in the wild.

She said the zoo had no plans to get any more snow leopards but she did reveal that Sheva and Bhutan's old enclosure was being overhauled to welcome a new species the zoo has not had before.