Microchips and tattoos are also great for ensuring your dog doesn't end up in a laboratory. Those who use dogs for experiments cannot touch one that has a chip or tattoo, and some animal control departments actually sell dogs to laboratories rather than euthanize. Medium sized breeds such as Coonhounds, spaniels and beagles are the most common victims. Obviously tattoos can be hard to read though, and even harder to know what the number refers to in order to find an owner. Microchips can be updated free for life, once the initial registration fee has been paid.