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.
Britain's only pandas have just one more chance to breed successfully, as time runs out.
On Wednesday "natural sparks" flew between Yang Guang and Tian Tian, but the pair failed to mate, as the female bear's limited window of fertility draws to a close.
Keepers at Edinburgh Zoo opened a "love tunnel" between their enclosures after tests showed Tian Tian had ovulated.
They met five times on Tuesday and "several times" on Wednesday but failed to ignite the "spark".
The pandas will have a final chance to mate on Thursday but keepers are losing hope that Tian Tian will get pregnant this year.
– Edinburgh Zoo
The pandas met again twice this evening and on their first meeting came closer than ever before to mating. If Tian Tian’s hormones are still partially elevated, we may put Tian Tian and Yang Guang together for one last time early tomorrow morning.
Edinburgh Zoo has posted footage of pandas Tian Tian and Yang Guang 'wrestling' inside their enclosure.
Iain Valentine, Director or Research & Conservation, said: "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."
Edinburgh Zoo says the chances of pandas Tian Tian and Yang Guang producing babies this year has "decreased."
– Edinburgh Zoo
Although the furry pair have hit it off and have a definite attraction, no full mating has been seen to date.
The pandas will have one or two final meetings later this afternoon and potentially early this evening, however chances of the panda pair achieving a successful mating this year have decreased.