Photo taken on May 22, 2015 shows giant panda twins Mei Lun and Mei Huan at Zoo Atlanta, Georgia, United States. Born on July 15, 2013, Giant panda twins Mei Lun and Mei Huan at Zoo Atlanta are the first surviving pair of panda twins ever born in the United States. They are weaned and now occupy a separate habitat from their mother Lun Lun. (Xinhua/Wang Lei)
People visit giant panda twins Mei Lun and Mei Huan at Zoo Atlanta, Georgia, on May 22, 2015. Born on July 15, 2013, Giant panda twins Mei Lun and Mei Huan at Zoo Atlanta are the first surviving pair of panda twins ever born in the United States. They are weaned and now occupy a separate habitat from their mother Lun Lun. (Xinhua/Wang Lei)
Photo taken on May 22, 2015 shows the staff members cleaning dwelling of giant panda twins Mei Lun and Mei Huan at Zoo Atlanta, Georgia, United States. Born on July 15, 2013, Giant panda twins Mei Lun and Mei Huan at Zoo Atlanta are the first surviving pair of panda twins ever born in the United States. They are weaned and now occupy a separate habitat from their mother Lun Lun. (Xinhua/Wang Lei)
Photo taken on May 22, 2015 shows giant panda twins Mei Lun and Mei Huan at Zoo Atlanta, Georgia, United States. Born on July 15, 2013, Giant panda twins Mei Lun and Mei Huan at Zoo Atlanta are the first surviving pair of panda twins ever born in the United States. They are weaned and now occupy a separate habitat from their mother Lun Lun. (Xinhua/Wang Lei)
Combo photo taken on May 22, 2015 shows giant panda twins Mei Lun and Mei Huan at Zoo Atlanta, Georgia, United States. Born on July 15, 2013, Giant panda twins Mei Lun and Mei Huan at Zoo Atlanta are the first surviving pair of panda twins ever born in the United States. They are weaned and now occupy a separate habitat from their mother Lun Lun. (Xinhua/Wang Lei)
Photo taken on May 22, 2015 shows giant panda twins Mei Lun and Mei Huan at Zoo Atlanta, Georgia, United States. Born on July 15, 2013, Giant panda twins Mei Lun and Mei Huan at Zoo Atlanta are the first surviving pair of panda twins ever born in the United States. They are weaned and now occupy a separate habitat from their mother Lun Lun. (Xinhua/Wang Lei)
Photo taken on May 22, 2015 shows giant panda twins Mei Lun and Mei Huan at Zoo Atlanta, Georgia, United States. Born on July 15, 2013, Giant panda twins Mei Lun and Mei Huan at Zoo Atlanta are the first surviving pair of panda twins ever born in the United States. They are weaned and now occupy a separate habitat from their mother Lun Lun. (Xinhua/Wang Lei)
People visit giant panda twins Mei Lun and Mei Huan at Zoo Atlanta, Georgia, United States on May 22, 2015. Born on July 15, 2013, Giant panda twins Mei Lun and Mei Huan at Zoo Atlanta are the first surviving pair of panda twins ever born in the United States. They are weaned and now occupy a separate habitat from their mother Lun Lun. (Xinhua/Wang Lei)
Photo taken on May 22, 2015 shows the staff members cleaning dwelling of giant panda twins Mei Lun and Mei Huan at Zoo Atlanta, Georgia, United States. Born on July 15, 2013, Giant panda twins Mei Lun and Mei Huan at Zoo Atlanta are the first surviving pair of panda twins ever born in the United States. They are weaned and now occupy a separate habitat from their mother Lun Lun. (Xinhua/Wang Lei)
Photo taken on May 22, 2015 shows giant panda twins Mei Lun and Mei Huan at Zoo Atlanta, Georgia, United States. Born on July 15, 2013, Giant panda twins Mei Lun and Mei Huan at Zoo Atlanta are the first surviving pair of panda twins ever born in the United States. They are weaned and now occupy a separate habitat from their mother Lun Lun. (Xinhua/Wang Lei) 10
Photo taken on May 22, 2015 shows giant panda twins Mei Lun and Mei Huan at Zoo Atlanta, Georgia, United States. Born on July 15, 2013, Giant panda twins Mei Lun and Mei Huan at Zoo Atlanta are the first surviving pair of panda twins ever born in the United States. They are weaned and now occupy a separate habitat from their mother Lun Lun. (Xinhua/Wang Lei) 11
Photo taken on May 22, 2015 shows giant panda twins Mei Lun and Mei Huan at Zoo Atlanta, Georgia, United States. Born on July 15, 2013, Giant panda twins Mei Lun and Mei Huan at Zoo Atlanta are the first surviving pair of panda twins ever born in the United States. They are weaned and now occupy a separate habitat from their mother Lun Lun. (Xinhua/Wang Lei) 12