A microchip is a rice sized transponder, on which a unique number is embedded. The microchip is inserted using a needle between the shoulder blades of dogs and cats. The unique microchip number of your pet is then registered in a data base. The data base should include the owner's current telephone number, address and an emergency contact number. Any important medical information can also be entered into the data base. Most shelters, emergency clinics and veterinary clinics in Canada use readers or scanners as part of dealing with lost pets. When a lost pet with a microchip is identified, the microchip company is then contacted. Information in that pet's data base is used to located the owner's. It is, therefore, important to keep your pet's as well as your own information up to date in the database.