The aftermath of the warm winter was a "baby boom" of rats in April, a month in advance, said animal husbandry officials in Altay Prefecture in northern Xinjiang.
The rats were threatening two million hectares of the pastureland in Altay, about 20 percent of the total in northern Xinjiang, and could cause epidemics among the locals, they said.
The regional animal husbandry bureau based in Urumqi has been forced to send two helicopters to spray 20 tons of raticide in the worst-plagued areas over the past week to reduce the damage.
But officials said they had to be extra careful with raticide, which polluted the environment and could also poison foxes and eagles that preyed on rats.
The average temperature in Xinjiang during the past winter was two to four degrees Celsius higher than normal, and snow in the remote mountains in Altay shrank by at least 32 centimeters, according to the regional meteorological bureau.
(Xinhua News Agency May 15, 2007)