Chinese try to curb 'plague of desert rats' in Tibet with contraceptives

Pika, relation of the rabbit, blamed for increasing desertification. But experts claim rodents help sustain biodiversity
Plateau Pika
Plateau pika, Ochotona curzoniae, also known as a black-lipped pika, on the Tibetan plateau in Qinghai province, China. Photograph: W. K. Fletcher/Science Photo Library

China's authorities have scattered 200kg of rodent contraceptive pellets across the Tibetan plateau to control what they describe as a "plague of desert rats".

The growing number of rodents have been blamed for destroying fragile high-altitude grasslands and accelerating the spread of deserts.


China's chemists custom-designed the drugs to induce abortions and prevent pregnancy in "gerbils", according to the state-run Xinhua news agency. It is possible they are referring to pika, a small cousin of the rabbit with rounded ears and long whiskers that has long been the target of government eradication campaigns.

Government workers began spreading the contraceptive in the Gurbantunggut desert last May, leaving it in pellet form near the entrance of burrows. Since then they have reportedly distributed 200kg of the drug over 49,000 hectares in China's western region of Xinjiang. They say the drug will have a minimal impact on other animals.

"It's a good way to tackle the desert rat plague," local forestry official Du Yuefei was quoted as saying. He claimed populations of the pest have declined almost 10% as a result of the eradication campaign.

Pika and other rodents are accused of contributing to China's alarming desertification problem by over-eating grass and digging into the soil.

But foreign zoologists say the epidemic of the small mammals is a symptom rather than the cause of grassland degradation, which is mainly the result of human behaviour such as the exploitation of water resources and over-grazing.

"That the pellets have 'little effect' is highly debatable," said a conservationist who asked for anonymity. "All drugs have an effect when put into a system, on other rodents, on birds of prey that eat the rodents and so forth … It's business as usual — attack nature and hope for the best."

Conservationists say the small animals are an important source of food for bigger species such as bears, eagles and leopards, while their burrowing adds to the moisture of the soil.

Previous attempts to cull pika numbers, including mass poisoning campaigns and the construction of hundreds of perches for owls and eagles, have failed or had limited success.

Mass poisonings and the deliberate introduction of disease can hurt other wildlife and spread across borders, as was the case when Australia introduced myxomatosis to reduce the rabbit population in the 1950s.