Last year's breeding season wasn't disturbed by visitors, so it was only natural for Cloud and Zhuangzhuang to mate successfully.
As for how long after mating one can know if there is a pregnancy, that's quite difficult to say!
Panda gestation periods are quite peculiar, ranging from 70 to 320 days, meaning that the longest gestations can be eight months longer than the shortest, a four or five-fold difference in time!
By the time other babies are born, some pandas still show no signs of pregnancy.
It's said that Nezha from the mythical legends was born after a gestation of three years and six months, probably inspired by pandas.
Not only is there a wide range for the gestation period, but false pregnancies are also common.
Some female pandas even pretend to be pregnant every year just to enjoy the air conditioning and avoid going out...