The incident took place in Chakrawaparah village of Khamba taluka in Amreli district when a lioness chasing her prey, a blue bull, fell into a well and died, they said.
During the chase, the blue bull also fell into the well, forest officials said.
A part of the Sasan Gir forest, the last abode of Asiatic Lions, falls in Amreli district, where lions are found roaming freely and sometime hunting their prey.
Lioness are in the category of schedule-1 species, whose existence is considered to be on the verge of extinction.
During the recently concluded census in Gir forests it was found that there are 411 lions in the area.