Ok, maybe somebody has some information, or can add some validity to this... My friend went on a date with this girl he met online and she said that as a hobby she is into tanning small batches of leather and making little accessories with it. Ok, this is pretty cool, but she also claims that recently she go into this new kind of tanning where one of the steps involves smearing smushed rat brains onto the hide. Is this a real thing, or is this girl planning on smearing my friends brain onto some cow hide in the near future?
Edit: Holy shit, I think I answered my own question... http://www.braintan.com/articles/furs/miller1.html
Every critter has enough brains to tan it's own hide, except buffaloes (and some people I know).