The Toronto Zoo's four giant pandas are now heading off to the Calgary Zoo after captivating visitors for a final time on Sunday.

"They just won everyone's heart," Maria Franke, the zoo's curator of mammals told CBC Toronto. "I'm just going to miss the animals and their antics. Calgary is very lucky to get these animals for sure."

Da Mao and Er Shun, two giant pandas who have been on loan from China for the last five years, and two-year-old twin cubs, Jia Panpan and Jia Yueyue, were a staple of the zoo, and now zoo staff are preparing them for their big move to Calgary.

Toronto Zoo's mammal curator, Maria Franke, said she's watched the twin panda cubs grow from 'wiggly blind little' babies to 'roly-poly 2-year-olds.' (Toronto Zoo/Canadian Press) Franke explains that the animals are incredibly special because they're the first giant panda breeding pair in Canada.

And while the news that Er Shun was pregnant was exciting, twins put Franke over the top.

"I got a call from our senior vet basically saying we found a heartbeat, and I thought he was pulling my leg," she said.

"Then, a week later, we're following up and doing another ultrasound and we actually found a second heartbeat. And those moments were just like, 'Oh my gosh, we did it, she's pregnant and we're going to have twins.'"

Winning hearts virtually

Jennifer Etty, an early childhood educator in St. Catharines, Ont., is one of the pandas' and the zoo's biggest fans.

"Toronto Zoo has been a part of our family for many, many years," Etty told CBC Toronto.

She tries to make it out to the zoo two or three times a year, but once a week she visits the pandas virtually via the zoo's Panda Cam and through the videos the zoo posts on social media. In fact, Etty makes viewing the pandas a part of her activities with the pre-kindergarten group she works with.

Jennifer Etty visited the Toronto Zoo to see the pandas for the last time a few weeks ago. (Submitted)

"They all think that they're really funny because they roll around, they fall off of things, they're awkward," Etty said, adding, "They learn about how animals need to be taken care of, how they can be observed … they can watch them from a distance and admire what they are and help them exist within the world."

Etty is close to tears thinking about the pandas leaving her province, but as soon as the video feed is up in Calgary, she said she will be regularly checking in with the bears again.

Calgary expects 25 per cent increase in visitors

For its part, the Calgary Zoo, which will open its panda exhibit May 7, is expecting a 25 per cent increase in visitors in the first year, according to zoo spokesperson Trish Exton-Parder.

"We're just counting down the days now for our turn," she told CBC Toronto.

Jia Panpan (translated to Canadian Hope) and his sister is Jia Yueyue (Canadian Joy) play together at the Toronto Zoo. (David Donnelly/CBC)

Exton-Parder said the Calgary Zoo has spent quite a bit of time and energy getting ready for the family, building a new habitat called Panda Passage. Some of the keepers have been training in China.

When the bears arrive out west, one of Toronto's keepers will stay for a week to help ease the transition into the animal's new home.

'Going in the right direction'

Both zoos are part of a breeding program, called the Species Survival Plan, meant to increase endangered species' numbers in captivity. Last year, Franke said the giant panda was downlisted to "vulnerable" from "endangered."

Franke says the captive population is now at 520 bears and Chinese conservationists are slowly introducing some of them into the wild.

"Little steps, but we're definitely going in the right direction," she says.

After about a year and a half, the two cubs will leave Calgary, but Exton-Parder says that will make way for another chance for Er Shun to breed.

And, of course, that'll mean more impossibly adorable moments to share with Canada and the world.