Despite being set up on a romantic date by zookeepers, a pair of Chinese pandas at Edinburgh Zoo failed to mate, the zoo said on Thursday.
"Tian Tian (meaning Sweetie) and Yang Guang (sunshine) will not have babies this year because they didn't mate," Edinburgh Zoo's press officer told China Daily.
The panda breeding season for 2012 has ended, and both pandas are back on display, the press officer said.
The latest attempt to mate followed other attempts on Tuesday and Wednesday. Tian Tian and Yang Guang showed signs of chemistry and interest in each other, and wrestled a lot, but that was it.
Zookeepers had hoped to put the two pandas together for one last attempt on Thursday morning, but the hormone levels of Tian Tian, the female panda, were too low, and limited breeding behavior was observed in both pandas.
Female pandas ovulate just once a year and have only a 36-hour window in which they can get pregnant.
Based on a combination of hormone-testing and behavioral observation over several weeks, experts decided that the time was right for the pair to properly meet for the first time on Tuesday.
The zoo's "panda cams", which allow people to watch the animals online, were turned off so Tian Tian and Yang Guang could have their dates in private.
"Each time the pair met we saw a huge amount of eagerness and attraction between Tian Tian and Yang Guang. There was lots of vocalization and encouragement from our female and physical contact between the two," Iain Valentine, director of research and conservation at the zoo, said in a press release.
"He mounted her several times. However, full mating did not occur. Although both have bred before and have borne cubs with other pandas, they are both still relatively inexperienced," Valentine added.
"We are hugely encouraged by how much the natural sparks flew between the two animals. As with humans, not all male and female pandas are attracted to each other. Both were keen to mate, but their inexperience showed," Valentine said.