Tian Tian, the Chinese female panda in Edinburgh Zoo, may be pregnant, the zoo revealed on Friday.

Test results on Tian Tian's hormone and protein levels suggest she may be expecting a cub. The zoo artificially inseminated the panda on April 21.

Tian Tian, the only female panda in the UK, may be pregnant, Edinburgh Zoo officials said. Rob Mcdougall / FOR CHINA DAILY

Zoologists said changes in her behavior, including a lack of appetite, mood swings and exhibiting signs of nesting, were further indicators that the long-awaited pregnancy may soon become a reality. If a cub is born, it would be the first birth of a panda in the United Kingdom.

Tian Tian's possible pregnancy has been covered by much of the British media and many Chinese people in the UK told China Daily that they were excited about the recent development.

Zhao Biao, who works in London, said, "My wife and I are planning to bring my daughter to the zoo to visit the panda and cub.”

But the zoo also buffered the excitement by saying that a pseudopregnancy, in which female pandas show physiological and behavioral signs of pregnancy without actually being pregnant, is possible. Many female pandas undergo pseudopregnancy and Edinburgh Zoo is using a battery of tests to try to rule it out.

Zoo officials said it will take approximately 40 to 55 days for Tian Tian to either give birth to a cub or end a false pregnancy. Tian Tian's cub could be born between late August and early September.

"We cannot tell definitively at this stage if Tian Tian is pregnant or not, although we're seeing results that give us cause for encouragement,"said Iain Valentine, director of the panda program at the Royal Zoological Society of Scotland.

Valentine said it's also reasonable for Tian Tian to have twins by different fathers because the zoo used two different specimens in the artificial insemination. One specimen was taken from the zoo's male panda, Yang Guang.

"It's hugely exciting."Valentine said.

But he added: "Confirming a female panda's pregnancy is never straightforward and we would encourage people to try not to get too excited just yet.”

Further results from hormone tests will be available by mid-August, he added.

Tian Tian and Yang Guang arrived in Scotland in December 2011 and are the UK's only pair of pandas. After their arrival, Edinburgh Zoo instantly became one of Scotland's most popular attractions. The zoo received more than 800,000 visitors last year, a jump from 525,000 in 2011.

Both pandas will turn 10 in the next few weeks and have tried and failed to mate on two occasions. Zoo officials then decided to have Tian Tian artificially inseminated.

On the advice of the China Conservation and Research Center for the Giant Panda, a team of experts in artificial insemination and reproduction from around the world joined the Royal Zoological Society of Scotland staff to carry out the procedure.

The panda team at Edinburgh Zoo is closely monitoring Tian Tian and the panda enclosure is open to visitors as normal.

Related stories:

Edinburgh zoo says giant panda may be pregnant

1st anniversary for Chinese giant pandas at Edinburgh Zoo

Chinese panda pair arrive at Scotland's Edinburgh Zoo

Edinburgh Zoo?ready for China's pandas