 Researchers from the University of Belgrade's Biology Faculty calculated that even the smallest bats can eat up to 3,000 mosquitos per night, which may explain the apparent lack of mosquitos in the Resava valley and on the slopes of the Beljanica mountain.Resava cave was accidentally discovered by the local shepherds in 1962.After being explored for 10 years, the cave was officially opened for visitors on 22 April 1972.