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Microchipping Could Save your Pet's Life
Revised: July 15, 2023
Published: August 02, 2017

Microchip implanter and dog
Photo courtesy of Depositphotos

A microchip ID is a small transmitter about the size of a grain of rice. When a scanner passes over it, a signal is emitted indicating the unique identification number of the chip. This tiny but sturdy little implant can reunite you with a lost pet, serve as proof of ownership in a dispute, or even mean the difference between euthanasia and medical care in an emergency. In many communities, it is not legal to own an unmicrochipped dog, and in many communities, shelters automatically microchip any pet that is released through its doors for adoption.

Microchipping has been around for over 20 to 30 years, yet some pet owners still resist chipping. Questions commonly arise about how the chip is inserted, what information is contained on the chip, the difference between a registered chip and an unregistered one, what to do if a chipped pet is lost, and more. There are many misconceptions about chipping. For example:

  • A microchip does not locate a missing pet.
  • The city shelter does not maintain a microchip registry (though they may very well include the chip information in its licensing database).
  • There is no central registry where all microchip information is maintained.
  • Personal information is not stored on the chip.

Don't forget to update your contact information with the chip registry when you move.

What Information is Encoded on the Chip?

Only the unique identification number is encoded on the chip. None of your personal information is on the chip. The chip number is similar to a Vehicle Identification Number on a car. It is registered in one of several central registries just as a car is registered and it is the central registry that has your personal information (name, address, phone number, alternate contact, pet description etc.). Each chip number is unique and no two chips have the same number.

Let's clear up some confusion.

Microchip Implantation: Basically a Shot With a Big Needle

Microchip and metal inserter
Photo courtesy of Depositphotos

The microchip ID is small enough to pass through the bore of a large needle made for this purpose. Microchips are generally shipped in an individually packaged syringe made for chip implantation. Implantation is basically a shot, and if you like, it can be done in the examination room while you watch. The needle is fairly large, so sometimes there is a yipe but, more often than not, the reaction is minimal. Chips can be implanted in newborn animals to assist in telling them apart. Some people like to wait until the pet is being spayed or neutered so that the pet does not feel the large chip implantation needle. The downside of waiting, of course, is that pets may escape or get lost before they have their permanent ID.

A common misconception is that chip implantation requires surgery. In fact, a chip can be implanted in a matter of seconds while you wait.

Can a Microchip be Used to Locate a Lost Pet?

No. A microchip is not a location device. At the present time, GPS collars are available, but their use is limited by the fact that a collar can be removed or can come off.

A microchip is an identification device, not a locator.

With All This Fancy Technology, Why Is an Old-Fashioned Identification Tag Included with the Chip?

An ID tag is usually provided with the chip. The ID tag has the chip number and phone number for the registry. The tag is not for your keyring or to keep in a drawer; it is meant for your pet to wear as a backup. If a lost pet is found by a neighbor, stranger, or basically by anyone who does not have their own handy chip scanner, they will see the ID tag and know who to call. The registry will either contact you or they will provide the finder with information on how to contact you.  It is important to periodically check this tag over the years as the markings on the plastic tend to fade, and if they are illegible, they will not be helpful. You can order replacement tags from the chip company or have engraved metal tags made by any of a number of pet tag companies, but be sure to include the registry phone number on the tag if you do.

What Happens If the Chip Does Not Get Registered?

It is vitally important that you register your chip. Simply having a chip will not bring your pet home to you. Many rescue groups, pet stores, and shelters will implant chips and let you know your new pet is chipped, but leave the registration (which usually requires a fee) up to you. Many animal hospitals will chip your pet and then give you the mail-in registration form to complete the process at home.  Be very clear about this point when you get a new pet that comes with a chip. It is easy for the registration forms to get mixed up in receipts, vaccination records, and other paperwork.

If a pet with an unregistered chip is found, it may still be possible to trace the owner. The manufacturer of the chip is usually identifiable from the chip number. The major microchip manufacturers keep records of the facilities to which they have sold their chips. In this way, the facility where the chip was implanted can be identified. If that facility has records, the owner may be identified and contacted. This process assumes the manufacturer keeps records (smaller companies do not), that the facility where the chip was implanted keeps records, and that the owner's phone number is the same. If there are no records, this all leads to a dead end. It is really important to keep your registration current.

If your chip is not registered and someone finds your pet and wishes to keep him, they may simply register the chip in their own name.

Often a chip is implanted, and the registration forms are given to you to fill out on your own.
If you do not send in the forms, the chip will not be registered.

Must the Chip’s Registration be Renewed Annually?

For the major brands of microchips, the answer is no. Once the chip is registered, that registration is indefinite. This is a good thing in that the chip never becomes unregistered after it has been registered. The problem is that people move or the pet changes ownership and the chip information is never updated. Some chip registries have developed deluxe programs that do require annual renewal largely as a means to remind you to keep your information current.

How Many Registries Are There?

There are many chip registries, and a chip can be registered in any of them. The good news is that most chip distributors have their own registries, and it is easy to find a chip’s most likely registry based on its number. For example, AVID chips are generally in the AVID database, HomeAgain chips are generally in the HomeAgain database, etc.

Because so many chip registries have emerged, it can get tricky to determine what registry to call when a found animal is located. The American Animal Hospital Association has developed PetMicrochipLookUp.org. This tool allows for a registered chip number to be connected to its registry. The registry can then be contacted for owner contact information. If the chip is not registered, then its manufacturer is identified, and it may be possible to trace the owner by tracing the chip to the facility where it was implanted, as described earlier.

It is important to consider the importance of the chip's registry. It is vital that the registry be identifiable from the chip number, as this will be how your pet is returned to you. If the pet is chipped but it is not possible to tell what registry to contact, the chip is useless. If the chip company does not participate in PetMicrochipLookUp.org, it will be very hard to determine where to call. Further, you need the registry to be reachable 24 hours a day and you want a company that is stable enough that you can count on its being in business for the entire lifespan of your pet.  It is tempting to look for bargains in microchipping, but this seems to be an area where it is best to stick to major brands and use their associated registries. One would think there was one single registry for all chips, but there is not, and one would think customer service would be consistent among registries, but it is not.

What Should Be Done for a Pet That Was Adopted With a Chip Registered to a Prior Owner?

Each chip company has its own policy for this situation. Some will require a written note from the original owner allowing registration change. Some companies attempt to contact the original owner for a defined amount of time, and if the owner is not reached, then the chip may be re-registered. Contact the chip company that issued the chip for instructions in this situation.

Is Licensing the Pet with the City Going to Register the Chip Automatically?

Don't count on it. When a dog is adopted from a city shelter, it is common for the dog to be issued a license and for a microchip to be implanted and registered, but this depends on the city. The dog license registration will include information about the dog's rabies vaccination, ownership, and microchip number, if there is one, but that is not the same thing as registering the chip. If the pet is found and brought to the shelter, the chip will identify him in the shelter's records but if the pet is found and brought anywhere else, identifying the owner will depend on whether or not the chip is properly registered.

What Should I Do If My Pet Is Lost?

Notify the chip company so that the chip number will be flagged as belonging to a lost pet. If the company has a system beyond its chip registry, your pet's photo (assuming you have uploaded one) will be circulated to local animal hospitals and shelters. Be sure the chip company has your correct telephone number and contact information should your pet be found. Be sure to check the local animal shelter and inquire as to how to proceed there. Posters around the neighborhood also help. Hopefully, your pet is wearing some sort of identification as well (such as the tag that came with the chip) so that you can be contacted by the finder directly.

What Do I Do if I Find a Pet?

Running the pet to a local animal hospital or shelter will allow for rapid scanning for the presence of a microchip. If a chip is discovered and it is registered, it should not be difficult to find the owner. It is amazing how long some animals are lost before someone thinks to scan them. If you find a stray dog or cat, be sure to have it scanned sooner rather than later in case someone is out there searching. If there is no chip or identification tag, check the lost ads in the local newspaper listings. If there is no match-up, you may be legally compelled to bring the animal to the local animal shelter as this will be where the original owner is likely to look.

Situations Where a Chip Can Mean Life or Death

Lost Pet

This is the obvious situation for which the chip ID was developed. If your lost pet is recovered by the local shelter or taken to an animal hospital as a lost pet, the pet is scanned, the number found, the registry contacted, and you will be notified. 


If your home is burglarized, you can bet the criminals involved will not be careful to leave your doors or gates closed when they leave. Your pet may wander away in this situation, and permanent identification may be needed to help your pet get home.

Natural Disaster

Earthquakes, floods, fires, mudslides, hurricanes, etc. all lead to pets being separated from their homes. In some cases, Animal Control must evacuate pets from a community into a central holding area. Being able to prove a pet is yours is invaluable in this situation, especially if your pet is difficult to identify from a photo or does not have distinguishing markings. After Hurricane Katrina, a number of rescued animals were evacuated to holding areas, and their photos were posted on the Internet. Many pets were frightened, and good photographs could not be obtained.


If a pet is injured while lost or injured while roaming - as in the case of an outdoor cat hit by a car - a good Samaritan might bring the pet to an animal hospital for care. A stranger may not be willing to cover expenses for a pet they found on the road, and if your pet has no identification, you may never even know what happened. A microchip allows you to be notified so that proper decisions can be made.

Don't forget to chip a pet before traveling with you. A traveling pet is unfamiliar with the area you are visiting and may be more likely to get lost

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