Alex Lieber
General Practice & Preventative Medicine


In 1997, a Lhasa apso named Lukee bolted from his yard in Los Angeles. That was the last his family saw of him. That is, until he was picked up by a local shelter in June 2001.

Animal control officers ran a scanner over him when they picked him up. Nothing. With overcrowding approaching crisis proportions in Los Angeles, animal control officials prepared to euthanize the now seven-year-old dog.

Following shelter policy, they ran another scan over the dog. This time they got a signal – this dog had an owner somewhere. The shelter contacted the microchip company, which keeps records of owners and contact information, apparently even after six years. They contacted the owners and the dog and family were reunited.

Some form of identification for your pet is vital. Of the millions of dogs and cats euthanized in shelters around the country, an estimated 30 percent of them are lost pets whose owners cannot be found. Shelters only hold “stray” animals for a short time – sometimes only for a few days. Without identification, they are inevitably euthanized unless adopted out.

Identification has evolved over the years, from collar tags to tattoos and, more recently, implanted microchips. All are still available, at a reasonable cost. But which one is best?

The short answer: combine the traditional collar tag with either a tattoo or a microchip. The reason is that the average person who finds a lost dog may not know to look for a tattoo and won’t be able to detect the microchip without a scanner. Often, the effort to contact the owner depends on how easy it is to do so.

Collar tags can provide immediate contact information. Along with the ID tag, your dog should wear his license, which indicates that he has been vaccinated against rabies.

Here are the individual advantages and disadvantages of different forms of identification.


These are a must. Tags immediately tell a shelter worker that this dog has a home and a family who miss him. Tags should have up-to-date information on the name, address and phone number of the owner, and the name and number of the veterinarian (if there is enough room).

The ID tag should be accompanied by the dog’s license tag, which tells whoever finds the dog that he has been vaccinated for rabies and is registered with the local government.

The tags should be attached to your dog’s collar. Unfortunately, collars can be lost or (if the pet is stolen) taken off, so you’ll want to have a backup method of identification. If you don’t like ID tags, you can get collars that come with a plate to engrave your information.


The Pet Protector System is a 24-hour, nationwide emergency system much like Medic Alert is for humans. All vital information about your pet is instantly available to the company’s emergency operators. Should your pet get lost or need emergency assistance of any kind, whoever finds your pet simply calls a toll-free number located on a special tag on your pet’s collar and a trained operator is there to coordinate the assistance your pet needs. For more information, click on Pet Protector System


Tattoos have been used to identify dogs (and cats) for many years. For some, a series of numbers and letters are tattooed on some part of the animal, such as the upper rear leg.

That number is registered with a company such as National Dog Registry or I.D. Pet, which can contact the owner. Some purebred dogs registered with the American Kennel Club are tattooed and registered with the organization.

The owner can also have his or her contact number tattooed on the pet, but this can obviously cause problems if the owner moves away or changes numbers. In addition, that’s a lot of data to tattoo on your dog or cat. The efficiency of tattoos is under debate. Some people say they are reliable, others say there have been cases where the tattoo had become illegible.

There is also the problem of location and convenience. The average person would have to know to look for a tattoo, then find the number to a registry to contact the owner. (The best course for that person may well be to contact the local shelter and inform them that they have found a tattooed dog.)


Microchips have been gaining in popularity, especially with the introduction of scanners that can pick up microchips made by different companies. The chip is very small, about the size of a grain of rice, and it is inserted in the back of the pet’s neck.

The chip remains safely within the dog, though it may shift a little over time. When a scanner is passed over it, the chip gives a number, which is registered with the microchip company. The company maintains the owner’s contact information.

As in Lukee’s case, not everything works as planned. The dog was just a few hours away from euthanasia because the scanner didn’t pick up the chip the first time. The pet needs to be thoroughly scanned to pick up the chip, not a quick swipe down the back. Fortunately, the shelter’s staff was thorough; they picked it up the second time around.

Many shelters have turned from tattoos to microchips, while others do both. Microchips have become much more popular. Whatever you choose, make sure to back it up with visible identification.