A dogfight among males for female attention has killed three rare one-horn rhinoceros in a wildlife sanctuary in West Bengal, forest officials said.

The officials said such rivalry threatened the animal's population.

These gory fights, often between young virile males who take on older rhinos to establish sexual supremacy, was to be blamed on a massive imbalance in the animal's sex ratio, officials of Gorumara National Park said.

Gorumara, situated at the foothills of the eastern Himalayas, has 25 rhinos-- an equal number of males and females and five cubs.

"The ideal male-female ratio is 1:2, but in our park there is a massive imbalance (in sex ratio)," Pinaki Mitra, deputy chief of Gorumara sanctuary, said.

Mitra said in the past nine months three rhinos had succumbed to injuries sustained in fights with younger challengers to woo female mates.

"We have recently treated a four-year-old male which suffered very bad wounds in one such fight," the official said.

He said the frequency of the fights among male rhinos is on the rise," something we are very worried about because such rivalry can be a threat to the animal's population."

"They (the fighting rhinos) don't get time to recuperate. The natural balance of population gets disturbed and this doesn't augur well for the rhinos."

But for their rivalry, the endangered rhinos in West Bengal's two wildlife sanctuaries are doing well. The bigger Jaldapara Wildlife Sanctuary has counted 96 rhinos in a new census.

"There is no threat to them (rhinos) from poaching. Their numbers have grown following a successful conservation programme," Mitra said. In 1985, there were a mere 14 rhinos in the two parks.

The single-horned rhino, found in the wild only in India, has their highest population in the Kaziranga National Park in the northeastern state of Assam, where officials said, 1700 rhinos grazed the vast marshy grasslands of the mighty Brahmaputra river basin.