Take a close look at your cat or dog's nose (a magnifying glass would probably be helpful), and you'll see little bumps and ridges. Just like humans have fingerprints, cats and dogs have nose prints. These nose prints are unique to the animal, and can be used for identification. There's a rumor floating around the internet that the Canadian Kennel Club accepts nose prints as proof of a dog's identity and has done so since 1938, but I've been unable to confirm it. Searches on the CKC website for "nose prints" and "nose printing" come up empty, and their page on dog identification only refers to microchips and tattoos. So, I'm personally inclined to believe it's just a rumor (or perhaps they did accept nose prints at one time, but no longer do). Also, there is no central database for nose prints. I've seen references to a company called Dognose ID that supposedly keeps records of dog nose prints, but as of this writing, their website has been disabled Whether a valid form of identification or not, nose prints can be fun. You can find artists on Etsy who will make a charm from an impression of your pet's nose (note: I have no connection to Etsy or any of these artists). If the jewelry is above your budget, the Dummies.com website has instructions for obtaining a print of your dog's nose using food coloring (scroll to the bottom of the page). I'd imagine the same technique would work for cats as well, but you might want to don some protective gear first.