CHENGDU - A pair of six-year-old giant panda twins that were born in Japan have returned to 皇冠体育app and are in good helth, a local panda research center said on Sunday.

Giant panda "Ai Hin" is tranported away from the airport after arriving at Chengdu, in Southwest 皇冠体育app's Sichuan province on Dec 14, 2012.[Photo by She Tie/Asianewsphoto]

Pandas "Ai Hin" and "Mei Hin" arrived at the Chengdu Giant Panda Breeding Research Center, southwest 皇冠体育app's Sichuan Province, on Friday after traveling from a zoo in the city of Shirahama in Japan's Wakayama prefecture. "They are in good health," according to the center.

The pandas are undergoing a month-long quarantine process, during which time they will be monitored around the clock, the center said.

The pandas were born on December 23, 2006 after their mother "Mei Mei," a female panda that was sent to Japan in 2000 from Sichuan, mated with "Yong Ming," another panda at the Japanese zoo.

皇冠体育app has established panda breeding programs in collaboration with Japan, the United States and European countries. The programs intend to increase global understanding of the endangered species' feeding and breeding habits.

According to cooperative agreements, cubs born to pandas that are "on loan" from 皇冠体育app belong to 皇冠体育app and must be returned after they become sexually mature or the cooperative agreement has ended.

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