Should You Microchip Your Dog?

Microchipping your dog is not mandated by law in the US, but animal welfare organizations, including the American Veterinary Medical Association (AVMA), the American Animal Hospital Association (AAHA), and the American Society for the Prevention of Cruelty to Animals (ASPCA) support the practice. 

More than 3 million dogs enter shelters each year in the US, according to the American Humane Association, and microchips play an essential role in getting many of those animals home. But according to pet microchip company HomeAgain, only 3 to 4 percent of those dogs have microchips. 

Read on to learn why microchipping your dog improves the odds he’ll return to you if he gets lost, and to get answers to the most common questions about the microchipping process. 

Why to Microchip Your Dog

A higher percentage of lost dogs with microchips are reunited with their owners than lost dogs without microchips, according to a 2009 study in the Journal of the American Veterinary Medical Association (JAVMA). The study of 7,700 stray animals found that dogs entering shelters without microchips were returned to their owners 21.9 percent of the time, while dogs entering shelters with microchips were returned to their owners 52.2 percent of the time. 

Dogs will dash through an open door or dig their way under the backyard fence. While ID tags, personalized dog collars, and GPS collars increase the chances your stray dog is returned home quickly—what if he runs off without a collar, or it comes off while he’s lost? Microchips are an essential backup measure for times when these identifiers are missing.  

Is Microchipping of Dogs Mandatory?

No. In the US, microchipping is not mandatory for dogs or other pets. But it is compulsory in countries of the European Union (EU), as well as in Australia, Japan, South Africa, United Arab Emirates, and many other countries. If you want to travel internationally or move abroad permanently with your dog, he’ll require a microchip that meets the standard of the International Standards Organization. 

Do Microchips Always Help Find Lost Dogs?

The AVMA research indicates dogs with microchips have a far greater chance of being reunited with their families if they have a chip. But the chip has problems, especially in the US where there is no standardized microchip frequency, and multiple scanner types exist that can read only particular frequencies. To help with this problem, ‘universal’ scanners that read every type of microchip are becoming the norm, though they are not in use everywhere yet. If you find a lost dog, find a veterinarian’s office or shelter with a universal scanner. 

In some cases, the scanners don’t detect the microchip. This may result from an error by the person scanning or, in rare instances, microchip movement after implantation. 

How Do Microchips Work?

Pet microchips are radio-frequency identification (RFID) devices that store a unique ID number. They are passive devices, which means they don’t have a power source, nor do they transmit any information via radio signal. Instead, a special scanner at veterinarians’ offices and animal rescues is required to read the microchip. Each microchip contains a unique ID number, which is used to locate the contact information for the dog’s owners in massive databases. 

The tiny capsule containing the microchip is made of a biocompatible glass, typically covered with a non-toxic polymer that prevents movement of the chip.

When a dog with a microchip enters a shelter, the staff or a veterinarian will scan them to search for the unique ID number, and then check that against the database. Next, the rescue staff or veterinarian will contact the owner to reunite them with their dog.

How Big Are Pet Microchips?

The devices are approximately the size and shape of a grain of rice. 

How Are Dogs Microchipped?

Dogs are microchipped by veterinarians who use a special bore-hole hypodermic needle to insert the device. The routine procedure doesn’t require anesthesia, but many people take the ‘two birds, one stone’ approach and opt to have the microchip implanted during surgery for neutering or spaying. 

The veterinarian will scan the microchip before implantation to ensure the ID code matches the information on its packaging. After the implant, the veterinarian scans the microchip again to make sure it’s readable.   

Perhaps the most crucial part of the procedure is ensuring you register with the microchip company. This is how your contact information becomes linked with the ID number in the microchip. 

Where Are Microchips Placed in Dogs?

Microchips are typically implanted in the subcutaneous tissue along a dog’s back directly between the shoulder blades, and oriented longways from head to tail. Uniform placement of the microchips helps veterinarians and shelter workers easily locate chips.

Can Microchips Move In Dogs? 

Yes—but this is rare. Typically, tissue at the implantation site quickly bonds to the chip, preventing migration. 

Since 1996, the British Small Animal Veterinary Association (BSAVA) has maintained a database of adverse reactions to microchips in more than 3.7 million animals in the UK. Microchip migration from the implantation site was reported only 229 times in dogs, cats, and other small pets between 1996 and 2009. 

But because of the rare instances of microchip migration, veterinarians and rescue workers will scan a stray dog’s entire body to search for a chip.  

Do Microchips Hurt Dogs?

The large-bore needle used to implant microchips may make dog parents wince, but the pain is minimal and short-lived—the procedure takes only a few seconds. Following the ‘pinch’ of the implant, there may be some minor inflammation at the needle site. The procedure in people that most closely parallels the ‘feel’ of microchipping in dogs, perhaps, is having blood drawn. 

Are Microchips Safe for Dogs?

The BSAVA database includes adverse reactions such as infection, swelling, and tumor formation—but these are extremely rare and reported in smaller numbers even than chip migration. 

Microchips can cause complications when improperly implanted. According to a literature review by AVMA, there’s been one report of a microchip implanted forcefully by the owner of a cat, and two incidents of implantation in the spinal canal of small-breed puppies. 

Do Microchips Cause Cancer in Dogs?

Current research does not support this notion, although a quick internet search reveals concerns that microchips cause cancer in dogs and other pets persist. Worries are understandable. After all, the chip is a device you are putting in your dog to protect him—the thought it could cause harm is troubling. 

Microchipped mice and rats used for cancer studies have developed tumors connected with the chips. But the mice and rat types in these cases had a higher risk of developing cancer. 

In a microchip FAQ page, AVMA states:

Tumors associated with microchips in two dogs and two cats have been reported, but in at least one dog and one cat the tumor could not be directly linked to the microchip itself (and may have been caused by something else). 

These instances are a handful among the millions of microchipped pets in the US, suggesting the risk of developing cancer from microchips is negligible. AVMA maintains that the benefits of having your dog microchipped far outweigh the risks.

Can Pet Microchips Be Removed from Dogs? 

AVMA recommends against having microchips removed because the risk of adverse effects are so low. Also, removing microchips requires a procedure that is more complex than implantation.  

Do Microchips Have GPS? 

No. Microchips are not GPS devices. If you lose your dog, you won’t be able to track him because of the microchip. But GPS collars for dogs enable you to locate your best friend anywhere in the world with a smartphone or other connected handheld device.

Microchip identification is a valuable fail-safe in the event your dog gets lost without his collar, or if it comes off after he’s gone astray.  

When Do You Microchip a Puppy?

Puppies are typically microchipped after they’re eight weeks old. Many people opt to have their puppy microchipped during spaying and neutering procedures, which typically occur between four and six months of age. This way, the puppy is anesthetized and won’t even feel the ‘pinch’ part of the procedure. 

If you get a puppy or adult dog from a rescue shelter, microchipping is often included in the adoption fee.

How Long Do Microchips Last in Dogs? 

Microchips are designed to be readable for approximately 25 years. Your dog’s microchip should remain effective for his entire lifetime.

Do Microchips Expire?

Once your dog is microchipped and registered with your contact information, the chip doesn’t expire. But keeping your contact information up to date is essential. Times you’ll need to update your dog’s microchip registration include:

• Moving to a new address
• Changing your phone 
• Adopting a microchipped dog from a rescue
• Adopting an adult dog from a friend or family member 

National Check the Chip Day (August 15) is an excellent opportunity to ensure your dog’s microchip is scannable and has the correct contact information. AVMA and AAHA sponsor the event with microchip company HomeAgain to raise awareness about microchipping and the importance of registration updates. 

You can search your dog’s chip registration information on the AAHA universal pet microchip lookup site with the ID number. 

Does a Microchip Prove Dog Ownership?

Pets are considered property under the law, and records of ownership can include microchips, registration and license information, and veterinary records. But the legalities can get muddy, and laws vary across states and municipalities.

Consider a hypothetical situation where a microchipped dog is lost and winds up in a shelter that doesn’t have a universal scanner. Following a waiting period (as determined by local law), the dog is adopted by a new family. Months later, their veterinarian discovers the chip during a checkup and finds the microchip registered to another family. What is the legal responsibility of the veterinarian or the family who has come to love the dog over the past few months? 

If you find a stray dog, you’re required to make every effort to find the dog’s original owner—including checking the dog for a microchip. But what about people who aren’t educated about microchips? Or, animal rescue workers who fail to scan during a busy period? Laws mandating that rescue and animal control workers scan for microchips exist in only nine US states.

The takeaway? The law surrounding pet microchips, ownership, and due diligence is still evolving.

For a device the size of a grain of rice—the microchip topic is big and complex and clearly sparks questions and concerns. Perhaps your best bet is focusing on the numbers. Millions of dogs are lost each year and more of them are returned home when they have microchips. If your best friend is ever lost without a collar—you’ll be glad you had probability on your side when you’re reunited.