Microchips identify dogs: they can't track location

It's easy to scan a dog to retrieve its microchip number
It's easy to scan a dog to retrieve its microchip number

Pete Wedderburn - Animal Doctor

While watching a Netflix sitcom recently, the story line intrigued me. A cat had gone missing, and its owners were trying to find it. They picked up their smartphone, and thanks to the microchip that had been implanted in their cat, they were able to track its precise location in real time.

This may have sound plausible to many viewers of the programme, but the truth is that, using today's technology, it's impossible to do this.

Location-tracking devices are available, but they are far too big to be injected in the scruff of the neck: they are around the size of a small matchbox. They can be attached to an animal via a collar, or placed on a harness, but they cannot be permanently implanted. The technology is continually improving and getting smaller, but we are still a few years away from having injectable location trackers for pets.

The current pet microchips cannot be used to track location: this is a common misconception, and the problem with programmes like the Netflix sitcom is that they can perpetuate this type of myth.

A microchip only achieves one simple task: storing and transmitting a fifteen digit number.

A fifteen digit number translates to a hundred trillion, which is the same as a hundred-thousand-billion. It's estimated that there are 500 million dogs in the world, which means that there are around two hundred thousand possible microchip numbers for ever dog. In other words, there are more than enough unique microchip numbers to go around, and there is no possibility of two dogs having the same number.

So a microchipped pet carries this "unique" number, and that's all. The microchip does not carry any extra information (like an owner's name and address), nor does it have the capacity to transmit the pet's location.

A microchip is tiny (around the size of a grain of rice). It contains a few electronic components enclosed in a capsule of bioglass, a silica-based, smooth, shiny substance that's widely used in a range of medical implants in human and animal medicine. The bioglass protects the internal electronics, and ensures that the animal's immune system doesn't react to the microchip. This is why a microchip can sit under the surface of the skin for many ears without provoking swelling, redness or pain. In contrast, if a grass seed or a splinter of wood manages to penetrate the surface of the skin, it causes a significant tissue reaction, and it needs to be surgically removed.

When a microchip scanner is passed over the skin of a microchipped pet, the implanted microchip is stimulated by a specific frequency of radiowave to emit its own radio signal in response. This radio signal contains one message: the fifteen digit number.

The scanner displays this number - the microchip number - on its screen.

The number is noted by the person doing the scanning, and it's then entered into the search box of the website of a Europe-wide secure online microchip database. This European database identifies which Irish microchip database contains the full details of the animal and its owner. It's then possible to go to the local Irish database website to retrieve the owner's name, address, phone number and email address.

It's compulsory for all dogs in Ireland to be microchipped, and for the number to be registered on an official database. What this means is that if any dog is found lost or straying, it should be possible to scan them, retrieve their microchip number, then identify their owner.

The law is one thing, and enforcement of the law is another. Nobody knows how many Irish dogs are microchipped, but I would guess that it's still significantly less than 90%. The new law has only been in place since 2016, and there must be many older dogs whose owners have not bothered to get their pets implanted. In theory, dog wardens could scan any dog in public to check them for a microchip, but in practice, this has not happened in any widespread way. It will take a few more years until it becomes standard practice to have all dogs microchipped.

And even when a dog is microchipped, this is only half the story: the microchip number still needs to be uploaded to a registered database with the owner's details. A fee must be paid to the database to store this information, and so many microchips remain unregistered. This means that when the dog's microchip number is entered into the European database, nothing will be found. There will be no online trace of the microchip number, and it will be impossible to identify the owner. An unregistered microchip is a waste of time: it performs no function whatsoever.

  • Is your dog microchipped?
  • Is the microchip properly registered on one of the official databases?

If you are not sure about the answer to these questions, ask your local vet. It's very easy for a vet to scan a dog and to check to make sure that the correct information stored online. And if it turns out that the microchip is not properly registered, it's very easy to sort this out. It will cost less than fifteen euro, and it could make the difference between your dog being returned to you or being permanently lost.