BEIJING, July 12 -- The killing of more than 2.3 million or 90 tons of rats in a two-week period signifies the magnitude of the problem around Dongting Lake in Hunan Province.

    The rodents invaded about 20 counties, mainly around Yueyang and Yiyang cities, leaving a trail of destruction in 1.6 million hectares of farmland. They were forced to flee on June 23 when the Yangtze River flooded, raising the water level of Dongting Lake.

    Residents had to beat them to death with clubs and shovels - a single blow killing as many as eight at a time. The message is: urgent measures must be introduced to combat this menace.

    It is not the first time rodents have created havoc in Hunan and some other provinces in recent years. About the same time last year, a similar incident occurred in the area, and was reported to be the most serious in a decade.

    This year, it is even worse with some villagers having to desert their homes.

    It is estimated that more than 300 hectares of paddy fields will bear no harvest this year, and more than 530 hectares have been seriously affected. Rat poison, traps and prevention barriers have been erected to contain the menace from spreading to even larger areas.

    No doubt we have yet to find better prevention methods to ensure it does not happen again.

    But what caused this huge population of rodents? The answer could be ecological imbalance, a rapid decrease in the number of snakes and owls, the natural enemy of rats.

    A snake can eat as many as 400 rats a year and an owl 1,500.

    Snakes in the region have been caught and exported to Guangdong in recent years and have ended up on the dining table. It has become a lucrative business, and depleted the number of snakes in areas around the lake.

    Owls have suffered the same fate. Some believe eating owls is a good cure for headaches.

    Mobilizing people to kill rodents is all well and good, but measures must also be taken to protect snakes and owls.

    A decrease in rodents depends on the population strength of snakes and owls.

    (Source: China Daily)