Though the exact cause of the death is yet to be ascertained, post-mortem indicated the presence of the snake’s head and portions of its tail. The tigress — whose carcass was found at Muthurayanakere in the Anechowkur range of Periyapatana reserve forest — was aged around 8 years.

There were no external injuries to suspect either territorial infighting or poaching, according to Assistant Conservator of Forests Balachandran.

The incident is suspected to have taken place two days ago and the tigress died on Monday and its carcass was found only on Tuesday, he added.

Veterinarian Umashankar, who conducted the post-mortem, confirmed the absence of any external wounds or even death by starvation in case the animal is incapacitated due to old age or injury.

“An apparently healthy tigress has died within hours of eating something and post mortem indicated the presence of parts of Russell’s viper. Starvation is ruled out as there was undigested meat inside while claws and skin was intact to rule out poaching,” he said.

There were also claws of a sloth bear and parts of pangolin which the tiger may have hunted before chewing on the snake and perhaps choking. It is extremely rare for a tiger to kill and eat a snake and rarer to die of poisoning injected by a snake and hence its death is suspected to have have occurred when the snake either bit it or when the tigress chewed on the fangs containing venom. But this is in the realm of speculation and the viscera has been sent to the Institute of Animal Health and Veterinary Biologicals, Bengaluru, for toxicology tests, said Dr. Umashankar. Officials say this might possibly be the first case to have been documented in the State if not in the country.

The carcass of another tigress was found in Nagarahole on Tuesday.

Park officials say it was in a highly decomposed state and the viscera has been collected and sent to the laboratory. The tigress, aged about 12 years, is suspected to have died of natural causes due to old age.