The highest number of deaths in captivity - 28- took place during 2009-10, while in the previous two years the figure stood at 25 and 22 respectively.

Though the data for this year is not available, the situation does not seem to be very encouraging given that as many as seven felines have died last month in Bannerghatta zoo in Karnataka, two due to old age while rest due to infection of salmonella bacteria reportedly after consuming stale meat.

The rest of the infected tigers, who are showing recovery, are being kept in strict observation and isolation in the Zoo, which has to its credit the highest number of big cats - 36- in captivity among the country's 54 zoological parks housing tigers.

Besides the tigers, two lions, a nilgai (blue bull) and a sloth bear also died in the park recently.

In all, there are 275 tigers housed in 54 zoological parks with Bannerghatta Zoological Park topping the list followed by Nandkanan Biological Park (16) in Orissa and Indira Gandhi Zoological Park (14) in Andhra Pradesh.

"Deaths due to old age is a natural process in any zoo or for that matter in the wild. But infighting and diseases are certainly a cause of concern. Zoo managers are instructed to take adequate steps," a senior environment official said.

In the wild, poaching and infighting besides man-animal conflict continue to threaten the survival of big cats whose numbers have dwindled to merely 1,411 in the country compared to 10,000 just a few decades ago.

At least 32 tigers have died in the wild so far since January of which six deaths took place this month alone with four reported from Kaziranga National Park in Assam, one each from Sariska in Rajasthan and Pilibhit in Uttar Pradesh due to infighting and poisoning.