Britain's only pandas have run out of time to mate as their limited breeding season drew to a close.
Tian Tian and Yang Guang had a window of just 36 hours to mate and despite "natural sparks" flying between them, the pair did not do the deed.
Keepers at Edinburgh Zoo hoped for one final chance to put them together today but test results late last night showed a drop in the female bear's hormone levels.
They met five times on Tuesday and several times again yesterday and had shown signs of attraction to each other.
However, the zoo said the level of interest had passed and limited breeding behaviour was seen in both pandas this morning.
The bears are now back on display.
A "love tunnel" between their enclosures had been opened on Tuesday when tests indicated Tian Tian had ovulated. They had shown "encouraging" signs, with male panda Yang Guang mounting Tian Tian, which led to the pair "wrestling".
Tian Tian had also "called out incessantly to Yang Guang" and pressed her paws and nose up to the grate separating them.
Edinburgh Zoo had turned off the "pandacam" which allows people to watch the animals online.
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Keepers say that while a baby panda would have been a "bonus", it is only the first attempt in a 10-year project.
Iain Valentine, director of research & conservation at the zoo, 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 10-year conservation project here at Edinburgh Zoo."
He added: "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 10 years."
Giant pandas Tian Tian (meaning Sweetie) and Yang Guang (Sunshine) arrived in Scotland from Ya'an reserve in Chengdu, China, on December 4 last year. They went on show to visitors for the first time on December 16.
They are the first giant pandas to live in the UK for 17 years and Edinburgh Zoo will be their home for the next 10 years.