Gnawing at a cat's tail but far from destruction

Rats, lots of them, have invaded farms around Dongting Lake in South China's Hunan Province. Estimates put the rat army at 2 billion as they continue to scurry their way through 20 counties of the province. The marshy banks of the country's second largest freshwater lake, with fiber-rich reeds to feed on and soft ground to burrow, provide the perfect habitat for the pests.

But rising water levels in the lake caused by flooding in the upper reaches of the Yangtze River have opened a Pandora's Box, forcing armies of the little critters out of their saturated holes on to the banks and into farms, villages and towns. The result has been devastating with the pests destroying crops on more than 1.6 million hectares.

So who do we blame for the sudden explosion in the number of rats? The floods? Or, the rich vegetation and insects they feed on? Alternately, is the pest menace sudden at all? None of these, say experts. Instead, they blame human intervention in the ecology and global warming for the menace.

The rat menace has been a long time coming, says Deng Zhi, a senior researcher with the Academy of Military Medical Sciences. The root cause of this menace is the reclamation of land from the lake. "Reclamation violates the laws of ecology. It not only facilitates floods, but also creates the ideal conditions for rapid rat reproduction."