Two giant pandas left Chengdu, capital of Sichuan province, for Canada on Monday.

Da Mao, a 4-year-old male from the Chengdu Research Base of Giant Panda Breeding in Sichuan, and Er Shun, a 5-year-old female from Chongqing Zoo, will stay in Canada for 10 years under a conservation agreement between the two countries.

"The duo will spend five years at Toronto Zoo followed immediately by another five years at Calgary Zoo,” said Zhang Zhihe, chief of the Chengdu panda base.

Da Mao, a 4-year-old male panda from the Chengdu research base, is ready for express delivery to Canada on Monday at Shuangliu airport in Chengdu. [Cui Kai / For China Daily]

Zhang said visitors to Toronto Zoo will be able to see the two pandas after a monthlong quarantine.

"The program will allow the Toronto and Calgary zoos to contribute to ongoing international efforts to increase the population of endangered giant pandas. Currently, fewer than 2,000 pandas remain in the wild,” he said.

Toronto and Calgary have waited for about 20 years to see pandas at their zoos again.

The Chinese tradition of sending the animals overseas dates to when the Empress Wu Zetian gave pandas to the Japanese emperor in 658.

On three occasions in the 1980s, Toronto, Calgary and Winnipeg zoos hosted Chinese pandas for short-term visits.

"Qing Qing and Quan Quan's 100-day stay in Toronto in 1985 drew hundreds of thousands of visitors. On the first two days, there were 35,000,” Zhang said.

Oliver Claffey was one of the keepers who looked after the pandas in Toronto in 1985. He thinks this visit will be even more successful than the first one because the pandas will be in the zoo for five years.

"This time, it's a long-term loan and I suspect that with the knowledge and staff we have at Toronto Zoo, the pandas will breed and that's the idea,” he told the Canadian Broadcasting Corporation.

FedEx, which has handled transportation for Da Mao and Er Shun to Canada, packed plenty of bamboo, bamboo shoots and apples for their more than 15 hour, 12,875 km journey.

Veterinarians from the Chengdu panda base and the Chongqing and Toronto zoos traveled with them.

Li Mingxi, a panda expert from the Chengdu base, said he will stay in Canada for six months to help Da Mao adapt to the new environment.

"Initially, we had arranged for Ji Li, a female panda, to head for Canada because the Chengdu panda base had been asked to supply a female, and Chongqing Zoo to provide a male. But because Chongqing Zoo had mistaken Er Shun for a male and discovered her gender very late, we had to let Da Mao take the place of Ji Li,” Zhang said.

With younger pandas it is more difficult to determine their sex and this is confirmed through genetic testing techniques, said William Rapley, Toronto Zoo's executive director of conservation, education and wildlife.

Tang Jiagui, a panda expert at Chongqing Zoo, said of Er Shun, "We did not find she was a female until an all-round examination in late November.”

News of the pandas' 10-year stay in Canada was announced by Canadian Prime Minister Stephen Harper when he visited China last year.

"It is a tremendous honor for Canada to be entrusted with two of China's national treasures,” he said.

huangzhiling@chinadaily.com.cn