BEIJING, June 13 -- Chinese zoologists claim to have discovered previously unknown passages through which wild Siberian tigers migrate between border areas of China and Russia, a finding that could help protect the extremely endangered species.

A 25-kilometre section between Xitong and Xilinzi in northeastern Heilongjiang Province, on the west bank of the Wusuli River, the boundary between China and Russia, has been found to be the main route for the species, said Sun Haiyi, deputy head of Heilongjiang Provincial Wildlife Research Institute.

A group of zoologists headed by Sun has been monitoring movements of the tigers in the border areas since January 2004.

The area to the east of Mount Wanda and the range of Mount Laoye in northeastern Heilongjiang shares a border of 600 kilometres with Russia.

Sun said the tigers crossed the border over the frozen Wusuli River during winter and swam across during other seasons.

Based on the monitoring results, Sun said there could be other crossing points for individual animals.

Siberian tigers mostly live in Northeast China and the far east area of Russia. They are estimated to number just 400 in the wild.

The monitoring carried out by Sun and his colleagues shows there are 10 to 14 Siberian tigers living in China.

Their habitat has shrunk drastically as a result of expanding human activities, putting the tigers on the verge of extinction, Sun said.

The discovery of the passage was significant to their recovery, Sun said.

Sun suggested government officials from China and Russia take active measures to protect tigers using the passage.

"That could lead to the increase in the number of wild Siberian tigers in both countries," Sun said.

Chinese scientists have made great progress in using artificial propagation to prevent the extinction of tigers, especially Siberian tigers, according to the State Forestry Administration.

To date, more than 1,300 Siberian tigers have been raised in China.

Last month, China Daily reported the Siberian Tiger Park in Harbin, capital of Northeast China's Heilongjiang Province, is expecting about 100 new cubs this year.

The park, which contains only Siberian tigers, is the world's biggest artificial breeding base for the rare species.

About a quarter of the park's 200 females of fertile age are expected to bring the total number of tigers there to more than 700.

However, park officials said the fast increase has obviously made the 144-hectare park's compounds more crowded and rendered its facilities inadequate.

(Source: China Daily)