A microchip is a tiny radiofrequency identification device (RFID) implanted under the skin, typically between the shoulder blades. It carries a unique 15-digit code registered in a database linked to owner contact details. Scanners at shelters and veterinary clinics read the chip instantly.
Lost animals without identification face uncertain fates: extended shelter stays, euthanasia, or permanent separation from owners. Microchipped animals are returned to owners at rates 2-4 times higher than unidentified animals, dramatically reducing unnecessary suffering.
Countries with mandatory microchipping laws (UK, Ireland, Australia) show higher reunion rates, reduced shelter intake, and better disease management. England's 2016 mandatory dog microchipping law increased reunion rates by 30% in participating shelters.
The microchipping procedure causes brief, mild discomfort comparable to a routine vaccination. No anesthesia is required. Chips are biocompatible and designed to remain in place for the animal's lifetime. Adverse reactions are extremely rare (<0.01%).
Multiple competing databases with poor interoperability reduce reunification rates even for chipped animals. Standardization of chip frequencies (ISO 11784/11785) and unified national databases are welfare-positive policy improvements. Owners must keep contact details current.
While dog microchipping is widespread, cat microchipping lags due to indoor-only assumptions. Outdoor, free-roaming, and colony cats particularly benefit. Microchipping is also used for rabbits, ferrets, reptiles, and birds with species-appropriate chip placement.