I was camping in central Nevada a few nights ago on a remote stretch of BLM land, and had left my vintage Rockhopper outside as I often do to get sleeping room in the back of my Jeep. Went to get the bike next morning (stashed out of sight behind a clump of sagebrush) and got an unpleasant surprise. The seat had big chunks taken out of it, with yellow foam hanging out, and the right side shift lever was abraded down to the metal. WTF??? At first I thought the seat had just gone brittle with age and cracked, but close inspection of the shift lever revealed telltale gouges of sharp teeth. It took me awhile, but a light dawned in my brain that seats and shift levers get covered with a tasty residue of salty sweat. I'm guessing that a porcupine helped himself to a snack during the night. Hope the bugger got a stomach ache!
Moral: Don't leave the bike on the ground when camping; stand it up or leave it on a rack.