Tian Tian in Edinburgh Zoo. /Photo courtesy of Edinburgh Zoo
It subsequently used artificial insemination with Yang Guang's semen and defrosted semen from a panda that had successfully bred at Berlin zoo.
One source said Valentine had complained that military jets taking part in Edinburgh's military tattoo would fly over the zoo during August, at a crucial moment in the panda's pregnancy, just as she was close to birth.
Valentine also felt there may have been links between Tian Tian's failure to give birth and seasonal changes in Edinburgh's daylight levels. Because the city is further north than their natural home in China, the longer days in summer and longer nights in winter may have upset her hormones.
