This giant panda has given birth to twin cubsCourtesy: Tokyo Zoological Park SocietyArrow pointing: Shin ShinLocation: Tokyo, JapanIt's the first time twin pandas were born at Ueno ZooPandas are notoriously difficult to breed in captivityas the females go into heat only once a year and can be picky about partners(SOUNDBITE) (Japanese) UENO ZOOLOGICAL GARDENS ZOO SPOKESMAN, NAOYA OHASHI, SAYING:"It is said that in most cases, when twins are born, only one will grow up. In order to raise both of them, we need to have one panda always be held by Shin Shin. We will have them take turns to nurse while the other one will be in an incubator. Once one panda finishes nursing, we will place that one in the incubator, and let the one who hasn't nursed yet be together with Shin Shin. We need to watch the feeding times for the pandas and perform this work around the clock for a few months. I believe this is the most difficult part."