By Huang Zhiling in Chengdu and Zou Huilin in Shanghai (China Daily)
Updated: 2007-10-29 07:32

Two pandas born in Japan four years ago became the first overseas-born twins to return to China Sunday.

Ryuhin and Shuhin, both males, left Osaka around 3:30 am (Beijing time) on October 27, stayed in Beijing overnight and reached the Chengdu research base of Giant Panda Breeding center Sunday afternoon.

The twins will be quarantined in a newly built house for two to three months before they are shown to visitors, Zhang Zhihe, chief of the base in Sichuan Province, said. The quarantine will not only check against any disease they might be carrying, but also help them adapt to the new environment.

Ryuhin and Shuhin were born on September 8, 2003, to Yong Ming and Mei Mei. The research base had leased Yong Ming and Mei Mei to the Adventure World Park Zoo in Wakayama in Japan in 1994 and 2000, respectively, under a Sino-Japanese cooperation program on panda breeding.

China has been involved in long-term giant panda breeding cooperation programs with Japan, the US and Spain since 1994.

"Mei Mei has given birth to nine cubs in Japan out of which seven have survived. Japan has more pandas than any other country except the Chinese mainland," said Jing Shimin, assistant to the director of the research base.

The first panda born in Japan, Yuhin, returned to China in June 2004. According to a cooperation clause, cubs born to pandas loaned to other countries have to be returned to China after they attain sexual maturity.

"In 2004, the cooperation program on giant panda breeding between the Chengdu Research Base of Giant Panda Breeding and the Adventure World Park Zoo in Wakayama was extended because of the results achieved," Zhang said.

Tanigaki Kunilo, a panda lover in Wakayama who accompanied the panda twins to Chengdu, said she was sad to bid "goodbye" to them. But the fact that they would live in the environmentally friendly base, which impressed her very much, made her feel happy for the twins.

Spread over 33 hectares, the base is home to 67 pandas and is surrounded by evergreen bamboo forests.

Giant pandas are one of the most endangered species in the world, with only 1,590 surviving in the wild, most of them in Southwest China's mountainous regions.

At the end of last year, about 210 giant pandas were living in captivity in China.

A panda is returning from the US, too. A four-year-old male panda Mei Sheng, born in the San Diego Zoo, is returning home to get "married".

"Mei Sheng (literally meaning "Born in the US") was born on August 19, 2003, the first to be born in the US without the help of artificial insemination, said Li Desheng, deputy director of China's Conservation and Research Center for the Giant Panda Wolong Nature Reserve in Sichuan.

San Diego Zoo veterinarians conducted a thorough medical check-up on Mei Sheng and announced he was ready for his airplane trip, Li said.

Zoo experts said they had collected a lot of information on giant pandas' growth and mother-cub relations, thanks to Mei Sheng and his mother Bai Yun.

Li said Mei Sheng's return was part of the cooperation agreement on panda research between China and the US. The US has to return a panda cub born to parents loaned out to it before it becomes sexually mature.