Let's get it on: giant pandas have a hot date in the 'love tunnel'

Edinburgh Zoo hopes Tian Tian and Yang Guang will mate for the first time within days

Yang Guang, pictured, and his mate Tian Tian have a 36-hour breeding window (PA)

The weather outside may be bitterly cold, but things are heating up inside Edinburgh Zoo’s £280,000 panda enclosure.

Keepers are hopeful the zoo’s two giant pandas could successfully mate for the first time within days as their annual 36-hour breeding window rapidly approaches.

Twelve months ago, the much-hyped tryst between female Tian Tian and male Yang Guang failed despite the pair showing “encouraging signs” and wrestling with each other. Along with habitat destruction, their infrequent reproductive urges mean they now number only 1,600 in the wild.

This year, zookeepers are taking no chances. Yang Guang’s radio has been switched from Classic FM to Smooth Radio, meaning he now enjoys the sounds of Marvin Gaye’s “Let’s Get It On”. The bear has been showing off his handstands, scent marking as high as possible in a display of virility. He and Tian Tian have also been allowed to swap enclosures to scent mark each others’ quarters.

And should Tian Tian fail to conceive naturally in the “love tunnel” that separates her pen from Yang Guang’s, experts from Berlin will be on hand to perform artificial insemination. A zoo spokeswoman said: “We could have baby pandas either way.”

Iain Valentine, director of giant pandas for the Royal Zoological Society of Scotland, said: “Tian Tian was showing hormone fluctuations. This suggests a hormonal crossover – which means the 36-hour window is between ten and 14 days away – mid-April has been suggested as a likely mating time.

“Interestingly, Tian Tian’s behaviour has started to change a lot over the past couple of days – she’s become grumpier, has gone off her food and has become a bit temperamental – basically a different panda to how she normally is,” he said.

“The strong behavioural changes seen already in Tian Tian do suggest things are about to start to happen, we just need to wait and see now, and carry on testing and observing.”

Samples of Tian Tian’s urine are collected twice a day for tests at the Centre for Integrative Physiology at the University of Edinburgh and Chester Zoo to help predict when the panda’s flash of interest in her mate will occur.

“If Tian Tian does fall pregnant, it will be in the second half of July or early August when Edinburgh Zoo experts will be able to tell by using ultrasound scans,” Mr Valentine continued. “Most giant panda cubs are born at the end of August or beginning of September.”

The zoo has been “packed” with visitors during the Easter period, and baby pandas would ensure a healthy boost to the attraction’s coffers.

The pandas cost the zoo £636,000 in fees to the Chinese for every 12 months of their ten-year loan, and bamboo – their principal foodstuff – adds another £70,000 to the bill annually.