Does bat shit actually cause insanity?

Otherwise, why describe someone as “bat shit crazy”?

I’ve read that toxoplasmosis, transmitted in humans primarily by contact with cat poop, is linked to certain kinds of schizophrenia… Perhaps as a factor in the “crazy cat lady” phenomenon (though that’s supposed to be more of an “animal hoarder” type of thing). Yet nobody’s called “cat shit crazy”. Just bat shit.

Any known reasons why?

Probably derived from the old “bats in your belfry” way of calling people crazy.

“moonbat” was a popular term for nuttiness not too long ago.

So “bat” has a strong history (of late, in our culture) of being associated with crazy.

And shit.

Not every phrase is literal.

Also, “Dingbat”, “Batty”.

Well, fruit bat shit certainly doesn’t!

I used to have a job that involved cleaning it up, and I’m perfectly frurbelwit gnap beeble!

Bat shit is a source of nitrates that can be used to make explosives. That’s why people who go nuts and start blowing things up are called… wait … this isn’t the fun facts thread is it?

http://boards.straightdope.com/sdmb/showthread.php?t=381630&highlight=bats+belfry