Eight tigers are missing from a reserve in western India, raising new concerns about the country's dwindling big cat population, a news report said Sunday.

The rare adult tigers have vanished from the Ranthambore National Park, which covers 60 square miles in the western state of Rajasthan, The Indian Express newspaper reported, citing the Wildlife Institute of India.

India has laws to protect wildlife and imposes severe punishment on violators. But lax enforcement, high prices for tiger skins and the use of their bones and claws in traditional medicine in neighboring China have created a thriving trade.

According to a census held in August 2005, Ranthambore had a total of 26 big cats — 21 adult tigers and five cubs younger than 20 months. By October 2006, another census showed a total of 31 tigers in the reserve but only 18 adults and 13 cubs — showing eight adult tigers missing from the count, the newspaper added.

"The sex ratio has improved a lot and we have a very good year with cubs, but all is not well," Fateh Singh Rathore, a former conservator at the tiger reserve, told the newspaper. "We need better patrolling and tracking by the park management if we are serious about saving the tiger."

In 2001, the U.S. National Geographic Society estimated that 5,000 to 7,000 Bengal — or Indian — tigers existed in the wild, about half in India.

However, conservationists believe official estimates of tigers in the wild are grossly exaggerated and that the true figure may be closer to 2,000 — or as little as several hundred.

This is not the first time that a large number of tigers have gone missing from Ranthambore; in early 2005 news reports had said that as many as 18 big cats had vanished from the park.