The partially putrefied carcass of the tiger was found by the patrolling staff last evening in a tank in the reserve area, the Reserve's Deputy Director Saket Badola said.
Preliminary examination of the carcass indicates it died about three days ago, he said.
Apparently, the big cat slipped and fell into the tank near the Seismographic Centre of Kalagadh Dam. The death seems accidental, he said.
Officials have reached the spot and a post-mortem is being carried out, he said.