"There's a possibility that Linhui might have ovulated twice. She may give births to twins," Zoological Park Organisation director-general Sophon Damnui said Monday.
According to him, two artificial inseminations have just been conducted for the panda couple.
"Every step in the process went on smoothly because we have extensively monitored the pandas' behaviours for a long period of time," Sophon said.
The Chiang Mai zoo has struggled to make its star residents - 9 year old Chuang Chuang and his 8 year old partner Lin Hui - mate since the pair arrived on loan from China in 2003.
Pornography, diets and sperm donation have all failed, but Thai authorities said that a rare cold spell early this year has boosted hopes that the country's famously celibate giant pandas could produce a cub.
Zoo director Thanapath Pongpamorn said temperatures that have fallen as low as four degrees Celsius (39 Fahrenheit) in January have in fact steamed up the pair.
They normally live in a climate-controlled room but they seemed happier with the cold weather.
Thanapath said Lin Hui has shown signs of being ready to mate, including following her partner around, and it has also helped that the cold snap has coincided with the regular mating season.
The cold snap did get them a bit hot and horny.
"Because of the readiness of their physical condition and the weather, we hope we will have good news soon," he said.
Lin Hui received semen from her companion in April 2007 after the pair showed no interest in reproducing the traditional way, but she failed to become pregnant.
The previous year Chuang Chuang, who had been deemed too heavy to mate with Lin Hui, lost seven kilograms (15 pounds) on a low-carbohydrate diet, and was then shown 15-minute video clips of successful panda couplings.
But the panda porn did little to inspire.
Giant pandas, notorious for their low sex drive, are among the world's most endangered animals. Nearly 1,600 pandas are believed to survive in the wild in China and about 180 are being raised in captivity in zoos worldwide.
