One-horned rhinos at the Gorumara National Park in Jalpaiguri. File picture

Jalpaiguri, March 28: The number of one-horned rhinos in Gorumara National Park has gone up in two years, but there is only one female for three males.

The ideal sex ratio is 3:1 or three females to one male.

Gorumara had 35 rhinos in 2010 and a census in 2012 showed an increase of 11 animals.

“The population of rhinos has increased in Gorumara but there is only one female for three males, which is just the opposite of the ideal ratio. The imbalance in the ratio is leading to infighting that causes injury and deaths,” said Sumita Ghatak, the divisional forest officer (wildlife-II).

“The mating and breeding time of the rhinos is from March to September. During this period, male rhinos fight among themselves for a mate and get injured. Some of the males even leave the forest,” she added.

A forest officer said a census in 2010 had put the number of rhinos in Gorumara at 35. “We conducted a count last year and found that the park has 46 rhinos now,” he said.

In Bengal, the one-horned rhinos could be seen only in Gorumara and Jaldapara Wildlife Sanctuary. “In Jaldapara, the population of rhinos is around 160 now,” said the forester.

He said infighting among the rhinos was common in Gorumara because of the improper sex ratio. “In the past three years, four males and one female rhino have died because of infighting. Also, two male rhinos lost their fight with a stronger one and walked out of Gorumara. They entered the Baikunthapur forest and never returned.”

He added that the male-female sex ratio was 3:1 in 2010 also.

The Jaldapara forest also faces the imbalance in the sex ratio. A decade ago, the Bengal forest department had brought two rhinos, a male and a female known as Ratul and Madhu, to Gorumara from Assam to balance the sex ratio.

“The rhinos were brought from Assam as there was no cross-breeding in Jaldapara. The duo were kept in enclosures so that they could mix with the local rhinos for breeding. However, the local rhinos did not accept the duo. Madhu died after some years, while Ratul was sent to the Calcutta zoo,” said a forest source.

The forest department has no idea as to how the sex ration could be made ideal.

“Although the population is on the rise, we have no clue as to how a right sex ratio can be achieved. We are worried over the infighting among the rhinos. There were incidents where male rhinos even killed cubs. This is another cause of concern for us,” said another forest officer.