Until now scientists thought there were about 1,590 giant pandas living in reserves in the mountains of China. Pandas, one of the world's most endangered and elusive animals, are dependent on bamboo found in that area.

But scientists from Britain's Cardiff University and the Chinese Academy of Sciences now think there could be as many as 3,000 there after a survey using a new method to profile DNA from panda faeces revealed there was more than double the number of estimated pandas in one reserve.

"This was surprising and exciting. In our opinion, the same parameters can be applied across the whole mountain range," Mike Bruford, professor of biodiversity at Cardiff University's School of Biosciences, told Reuters.

Bruford said the scientists, whose findings will be published in journal Current Biology on Tuesday, stumbled across this discrepancy in the population as they were studying the movement of male and female pandas and their territorial instincts to understand their behavior.

The study found about 66 pandas are living in the Wanglang Nature Reserve in Sichuan Province -- and not 27 as estimated in the latest national survey that was conducted in 2002.

Bruford said there was no way that panda births or migration could account for so large a discrepancy and based on this finding, there may be 2,500 to 3,000 pandas in the wild.

Understanding population trends for giant pandas has been a major task for conservation authorities in China for about 30 years with three national surveys carried out but the terrain is hard to survey.

The first two surveys showed declines in numbers but the most recent survey showed signs of a recovery, helped by the Chinese government setting up a network of natural reserves and enforcing anti-poaching and anti-logging laws.

Bruford said the next step was to replicate the British/Chinese survey using its DNA method in other reserves.

The challenge then is to think beyond keeping pandas in reserves and find ways to end their isolation because inbreeding and low genetic diversity remain a possible threat to the species' long-term survival, he added.

He said one way to do this would be to build corridors between the different panda reserves.