The carcass were spotted by local people yesterday who informed forest personnel, they said.
"The reason behind the death of the animals is yet to be ascertained and it will be known after the autopsy," Nabarangpur range forester Jagannath Prasad Bisoi said.
Though electrocution of the animals could not be ruled out, it would be knwon only after inquiry, Bisoi said.
People in the area lay electric wires on fields to prevent destruction of crops.
He said villagers and members of Vana Surakshya Samiti were being interrogated.