You don't know where that's been!

Strange things Ruby licks with intensity but for no obvious reason: her stuffed snake, the headboard, the corner of the wall, the balcony railing, the kitchen rug (well, the reason for that is obvious), the magazine stack (she favors the New Yorker), the corner of the coffee table, and the curtains. I could understand one or two little licks, but she does this for ages at a time. I have no explaination. My dog is a freak.