This is a very good photo, as it is extremely dark in there and so any kind of photography is a challenge. A fantastic exhibit with free-flying bats all around the place!
@snowleopard My current camera is pretty good in terms of getting photos in low light conditions and I used a shutter speed that was getting fairly close to the edge of what I can do while hand-holding the camera and not using any support.
I also admit that I slightly altered this image digitally, making it a bit lighter than the original was to show things well enough without diverging too far from the original (or at least I think I did that).
That said, I agree with you that it is a great exhibit with the free-flying bats - and quite a unique one too given the environment of the old cellar/crypt.
@FunkyGibbon True, but this is actually one of very few bat walk-throughs I have seen in the 50 zoos I have visited. Usually bats are kept behind glass. The only other walk-through bat exhibit I have seen was at Mondo Verde in the Netherlands, where they keep Egyptian fruit bats free-ranging in their tropical hall (although I only saw them at feeding time).