A pet microchip is a passive RFID tag, about the size of a grain of rice, implanted under the skin. It has no battery; a scanner's radio wave powers it just long enough to transmit a unique ID number.
That ID links to a registry with the owner's contact details. The system only works if the information is registered and kept current — a common, heartbreaking point of failure.
Unlike collars and tags, a chip can't fall off or be removed. Shelters and clinics scan every found animal, which is why decade-long reunions (like the 2026 cases) are possible.
Microchipping is quick, about as painful as a vaccination, and one of the highest-impact things a pet owner can do. Pair it with an ID tag for everyday safety.