The giant pandas at Edinburgh Zoo have failed to mate due to their "inexperience".
Tian Tian and Yang Guang had been placed in the same enclosure for the first time over the last two days in the hope they would breed.
But despite "eagerness and attraction" between the pair, they did not manage anymore than a playful wrestle.
Keepers had decided female Tian Tian was ready to conceive after taking a number of samples over the last few weeks and testing her hormone levels. It was decided that Tuesday and Wednesday was the window of opportunity for the pair.
Female pandas have just 36 hours every year in which they can get pregnant.
Iain Valentine, director of research and conservation, said the pandas were attracted to each other and the zoo had learnt a lot from the breeding season.
He said: "Each time the pair met we saw a huge amount of eagerness and attraction between Tian Tian and Yang Guang. There was lots of vocalisation and encouragement from our female and physical contact between the two. 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.
"At the end of the day, this is year one of a ten-year conservation project here at Edinburgh Zoo. We are hugely encouraged by how much the natural sparks flew between the two animals, as like humans, not all male and female pandas are attracted to each other. Both were keen to mate, but their inexperience showed.
"Baby cubs would have been a bonus this year, but we have to appreciate that the pandas have only just arrived and have had limited time to settle.
"Overall, we remain very pleased with the outcome of the last few weeks and it has been a fantastic trial run here at Edinburgh Zoo. As animal conservationists and scientists, we have learnt a huge amount in such a short time about this captivating species and we look forward to the next ten years."
The pandas arrived in Edinburgh in December as a gift from the Chinese government. It is hoped that in the next ten years they will have a baby.