The Expendables 2 has been shooting in Bulgaria, and it seems some of the area's nocturnal animals have suffered since production began. Bat experts have slammed the production for filming in The Devetashka Cave near Lovech, Bulgaria, claiming the bat population has dwindled significantly. Here's what Boyan Petrov of the Museum of Natural History had to say.

"Several thousand bats are missing from the Devetashka cave since our latest count in January when the visible colonies numbered 33,800 bats."
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Since production has started, the bat count is down to 8,500. The environment ministry approved the sequel's shoot in the cave, and claim they have found no problems with the bat colonies. However, bat experts such as Dobromir Dobrinov of the Green Balkans nature conservation group, believe filming should have never been allowed to take place in the cave.

"As a protected nature territory and important bat habitat, the cave is only open for visits by tourists and researchers and totally sealed during the breeding period in June and July."

Antonia Hubancheva, another bat expert, said the bats were subjected to the stresses of loud noise, bright lights, and crowds of people who kept them awake during their normal nocturnal period.