Animal rights groups attribute the situation to unscientific upkeep of the jumbos by their owners and mahouts.
According to rights groups, as many as 12 elephants had died under "mysterious circumstances" over the year and no serious investigation had been ordered by the authorities.
One elephant was struck dead by lightning at the open space it was kept ignoring the danger posed by summer showers accompanied by thunder and lightning.
The latest victim in the casualty list was a 38-year-old tusker which was struck by lightening as it was tethered in an open space in Kottayam district last week.
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Its custodians had not provided a proper shelter for the jumbo as prescribed by the rules.
Lack of sufficient fodder and water was found to be the cause of death of an elephant in Palakkad, they said.
The "Kerala Captive Elephant (Management and Maintenance) Rules 2003" has laid down comprehensive guidelines for the scientific upkeep of captive jumbos.