I'm not gonna make a huge post with wikipedia links, but bats are cool. They eat shitloads of insects that bother you every day. For fuck's sake, they are mammals that truly FLY (rather than glide, lots of animals can glide). That is rad as hell.
Bats in the US have been devastated by white nose syndrome in the past few years. It is a fungal infection that grows on the nose and wings of hibernating bats. Millions of bats have died, and it's a big fucking deal. Government conservation groups have closed caves infected with the fungus. Not to keep humans safe, but to keep the shit from spreading to more bats.
On the other hand, bats in Africa have been found to be the reservoir for some really nasty bacteria and virii.
My last apartment had bats roosting in the attic. Several got into the apartment over the years, and one was injured by my cats and would not live if released. I put it out of its misery with a large rock, and still have the dried corpse. For religious use only.
