Image caption Over-pampered temple elephants are being put on diets in Tamil Nadu

Authorities in India are being presented with a massive task - managing the weight of obese elephants kept in temples.

In parts of India, elephants are kept in temples for religious reasons - taking part in ceremonies and festivals.

Efforts are on in the South Indian state of Tamil Nadu to get these over-pampered tusked animals to slim down, officials have told the BBC.

Almost all the elephants kept in temples in the state have been found to be obese.

Accordingly, temple officials are reconfiguring the diets of their elephants on the advice of veterinary surgeons.

"The female temple elephant - 15 year-old Parvathi - is overweight by 500kg (80 stone) and efforts are on to reduce it," said Pon Jayaraman, executive officer of the Madurai Meenakshi Amman temple told the BBC Tamil service.

Another elephant in the Kallazagar Temple weighs 700kg more than the optimum for its age, according to Ravindran, the "Mahout" - or custodian - of the 48-year-old female elephant, Madhuravalli.

But veterinary surgeons point out that obesity and captivity go hand in hand.

Elephants eat up to 200 different varieties of food in the jungle, including fruits, flowers, roots and branches, but in captivity their diets often lack variety.

The experts also point out that the elephants in the wilderness are never exposed to foods such as rice, millets, salt and jaggery (an unrefined sugar set into blocks).

Uphill trek

Wild elephants wander, trek uphill, cross streams and walk on a variety of terrain. They also compete with other wild animals for resources.

A senior forest veterinary officer in the state observed: "In captivity, elephants eat constantly, and that coupled with lack of exercise makes the animals obese."

But temple officials say the elephants are taken for walks of at least 5km each day based on vet advice.

But research has shown that in the wilderness an elephant has to walk at least 20 sq km (eight sq miles) to find its daily food intake of about 250kg of plant matter.

'Grave sin'

Dr AJT John Singh, former director the Wildlife Institute of India, called the practice a "grave sin".

"It's like confining a solitary person in... the middle of the forest," he said.

"Elephants are social animals and have amazing social bonds with one another. Breaking that, and keeping the animal alone, is like solitary confinement, the greatest form of punishment to a human being."

Temple authorities say that a near natural environment has been created for the elephants. But this is strongly disputed by animal rights activists.

Many of the temple elephants throughout India - including 37 in the state of Tamil Nadu - are living in appalling conditions, studies have shown.

Superstitions add to the discomfort of the elephants. For example, astrologers suggest feeding elephants will ward off evil.

The reasonable option, according to Dr John Singh, would be for several temples to join together to buy a patch of land with natural cover, water and food so that the animals can wander and be brought to the temple on festive occasions.

Activists have long pointed out that keeping an elephant in a temple itself is abuse and a gross violation of animal rights.

Elephants were employed as war machines in India in ancient times, and a detailed account in the 2,000-year-old book Gajasastra even defines the methods for keeping an elephant healthy.

Vets point out that even feeding the temple elephants other than what they eat in their natural habitat indirectly amounts to abuse.