The UK's only female giant panda has been placed on 24-hour surveillance following hormone tests that indicate she could be pregnant and about to give birth.
Keepers at Edinburgh Zoo are now monitoring Tian Tian round the clock, even getting access to CCTV footage of her in their homes.
While it is not certain that the 10-year-old panda is pregnant, the latest hormone tests are reportedly showing positive signs. Experts suggest she could give birth any time in the next two weeks.
Zoo staff will be especially watching her for any restless behaviour and bleating, which are the signs of labour that would precede her waters breaking.
An experienced keeper from China with experience in assisting with births will be on hand to offer help with the birth. Haiping Hu, from the China Conservation and Research Centre (CCRCGP) arrived in Edinburgh on Saturday.
The birth itself could last only a matter of minutes as newborn panda cubs are extremely small, typically weighing around 100g.
Iain Valentine, director of giant pandas for the Royal Zoological Society of Scotland, said, “We have now entered the window of the possible time that Tian Tian could give birth.
”Keepers are monitoring Tian Tian on a 24-hour basis. They are able to log in from their computers and phones at home just to make sure everything is OK with her, and the keeper from China has now arrived to support us. We are ready.
“About 24 hours before she gives birth she will become quite restless, start moving around, and then will sit down, her waters will break and then quite soon after that she will give birth.
”The cub is only 100 grams, so she doesn't have to strain too much to give birth.
A spokeswoman from the zoo said pregnancy would be a “very sensitive period” for Tian Tian as her body could reabsorb any foetuses. Mr Valentine added that if she does give birth, her cub, or cubs, could be stillborn.
“We will keep our fingers crossed,” he said.
Chinese panda Tian Tian and her male mate Yang Guang are the country’s only pair of giant pandas. They arrived at Edinburgh Zoo in December 2011 after a 5,000-mile flight from China.
It was hoped that the pair, who are on loan from the People’s Republic, would mate naturally but animal experts ruled this out after assessing the female’s behaviour. She was artificially inseminated in April with semen from Yang Guang and another panda named Bao Bao, a “genetically important” bear who died at Berlin Zoo last year.
Tony Bradford, Visitor Experience coordinator at Edinburgh Zoo, said, “Nothing is 100 per cent yet, but it is still getting very exciting.
”Tian Tian is doing well, she is spending less and less time in public view, but visitors are being very understanding.
Any cub that is born at the zoo will be the first to be born in the UK. It will be the property of the Chinese state and will be expected to be returned to China when it is two-years-old.
In keeping with Chinese tradition, any cubs that are born would not be named until they are 100 days old and would only go on display on 1 January,2014.
Panda cubs have very little hair and are mostly blind as their eyes are firmly shut during the first few weeks of life.