Edinburgh Zoo has warned that the chances of Britain's only pandas successfully mating this year "have decreased."
Yang Guang and Tian Tian may be given one last opportunity tomorrow morning.
Female pandas only ovulate once a year.
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."
Breeding pandas in zoos is crucial to saving them from extinction. Actually, no not really.
The clock is ticking for Yang Guang and Tian Tian to mate within a limited window of fertility.
The last time Julie Etchingham reported on pandas was when she worked on BBC's Newsround in the mid 1990s.