More than 100 stray cats that used to roam city streets have been organized into an army to fight against rodents on the pastureland of northwest China's Xinjiang Uygur Autonomous Region.

The "cat army," which was delivered by the local pest control office to the grassland in May, have adapted to their new life and proven good rat hunters, said Li Hua, a forestry worker on the pastureland in Xinjiang's Bole City.

Li and his colleagues have observed fewer rats in areas where the cats wander. "Local herders also said they saw fewer rat holes," he said.

At least 5.4 million hectares of Xinjiang's pastureland was plagued by rats this spring. A total of 242 tonnes of rat poison was used to fight the pest.

To make the cats comfortable in the grassland, forestry workers have built pens for them near water sources.

"In winter, when the minimum temperature drops to minus 30 degrees Celsius, they will stay in local herders' homes -- these herders will get government subsidies in return," said Li.

He said cats are as efficient as foxes and eagles in rodent hunting. "We hope to promote the practice to the entire Xinjiang region and to other parts of the country."

Stray cats are an apparent consequence of China's fast urbanization over the past three decades: many old homes are demolished and pets are deserted when their owners move.

These deserted animals, plus those who went astray, often roam in schools, communities or around restaurants, relying on food provided by kind-hearted people or rummaging through garbage bins.

"They will prove valuable in pasturelands in China's western region," said Li Hua, who is drafting a report on the data he has collected since the cat army was brought in.