Mistaken identity

A dog was resting in a campground and an RVer was reading nearby on a lawn chair.

"Excuse me, sir, but does your dog bite?" a recently arrived camper asked. The RVer looked up over his newspaper and replied, "Nope."

Yet when the camper approached the animal, it began snarling and growling, and then attacked his legs. After pulling away from the crazed animal, he yelled, "I thought you said your dog didn't bite!"

The RVer muttered, "Ain't my dog."