Microchips have been particularly useful in the return of lost pets. They can also assist where the ownership of an animal is in dispute.

How does it work?

A pet owner brings it to a veterinarian that provides the service.
The veterinarian selects a microchip from their stock, makes a note of that chip's unique ID, and then inserts the chip into the animal with a syringe. The injection requires no anesthetic. It is about the size of a piece of rice and is inserted under the skin with a syringe just like a vaccination.
Before sending the animal home, the vet performs a test scan on the animal. This helps ensure that the chip will be picked up by a scanner, and that its unique identifying number will be read correctly.

An enrollment form is completed with the chip number, the pet owner's contact information, the name and description of the pet, the shelter's and/or veterinarian's contact information, and an alternate emergency contact designated by the pet owner.  The form is then sent to a registry keeper to be entered into its database. Depending on regional custom, selected chip brand, and the pet owner's preference, this registry keeper might be the chip's manufacturer or distributor, or an independent provider.

If the pet is lost or stolen, and is found by local authorities or taken to a shelter, it is scanned during intake to see if a chip exists. If one is detected, authorities call the recovery service and provide them the ID number, the pet's description, and the location of the animal. If the pet is wearing the collar tag, anyone who finds the pet can call the toll-free number, making it unnecessary to involve the authorities. The owner can also preemptively notify the recovery service directly if a pet disappears. This is useful if the pet is stolen, and is taken to a vet who scans it and checks with the recovery service.

The recovery service notifies the owner that the pet has been found, and where to go to recover the animal.