Collars and Tags
Every dog should have a collar and tags. It is the simplest, easiest way to identify your dog.A buckled collar is preferable to a choke chain for identification purposes, since dogs are more likely to slip out of a choke collar. The collar should be fastened securely so that it will not come off if grabbed. Dr. Duane Schnittker of the Brentwood Veterinary Hospital in Brentwood, California, offers this reminder: "Make sure the tags have current information. Usually, dogs are found within 3 or 4 blocks of their homes."

Types of tags
There are three kinds of tags: rabies tags, dog-license tags, and personal-identification tags.A rabies tag has a number, the year in which the shot was given, and the name and address of the veterinary office where the shot was administered. It is important to keep track of the year the shot was given because tag numbers are reused each year.Dog-license tags tell where the dog was licensed and feature a license number. The license number can be reported to animal control in the county and state where the license was issued to obtain the owner's name, address, and phone number. Personal-identification tags usually have the address of the owner on the tag. These are often available in cute shapes, like dog bones, fire hydrants, and so on. Sometimes a tag will have a kennel-license number and an individual dog-identification number. If you find a dog with a kennel tag, contact the appropriate county to find out which kennel was issued that license number.

Disadvantages of tags
* They are easily removed by unscrupulous people, like thieves, who can easily throw collar and tags away.
* The printing on tags may wear off over time.
* If the collar is not secure, the dog may slip out of it.

Tattoos
Tattooing is a permanent means of identification. Your dog would be tattooed with a series of numbers (for example, some people use their Social Security number) or letters and numbers. Your contact information is registered with an organization such as the National Dog Registry, ID Pet, or the (AKC) American Kennel Club (which registers tattoos of purebreds only).

Dogs are tattooed with similar tools to those used for humans, and the procedure appears to be relatively painless, though the noise may upset some dogs. The insoluble dyes in tattoo inks or pastes will not react with blood or tissues. On light-skinned animals, black ink is preferred; green ink is better for darker-skinned dogs.
The comparatively hairless inside of the earflap and inside of the hind legs or belly are the most common places to tattoo a dog. Some owners avoid ear tattoos if their dog's ears will be clipped later, and others are concerned that thieves may cut off the tattooed ear so they can sell the dog to a research facility. (Research facilities are not permitted to accept tattooed dogs.)
If you want to have your dog tattooed, consult your vet, breeder, or local humane society to find out more about the various registries and the tattoo they suggest. Each registry has pros and cons, and fees vary. In addition, animal hospitals generally maintain records of dogs they have tattooed. If practical, keep the tattooed area shaved for maximum visibility.

Disadvantages of tattoos:
* A tattoo can be hard to see or find; the individual who finds a lost pet has to be aware of tattooing and look for the tattoo.
* A canny crook can alter a tattoo.
* When you move, you must remember to update your contact information with the registry.
* Tattoos are not completely reliable as the only method of identification; they're best when combined with collars and tags and/or microchipping.

Microchips
The high-tech solution to dog identification is a computer microchip. About the size of a grain of rice, the microchip contains a coded number and is encased in a biologically inert substance so it can remain under the dog's skin for his lifetime. A microchip cannot be lost, changed, or removed.

A microchip is usually implanted in the loose skin between a dog's shoulders. Occasionally, microchips migrate; for this reason, some owners tattoo their dogs with a capital "T" within a circle to indicate that the dog has been microchipped. Then, even if the microchip migrates and is not instantly detectable, the shelter will continue to search for the implant.

Microchips should be implanted by licensed veterinarians. The procedure appears to be virtually painless—comparable to being vaccinated—and puppies as young as 8 weeks can be implanted. No maintenance is needed, and the microchip should last for 25 years. Ask your vet, breeder, or local humane society to recommend a microchip registry. Like tattoo registries, each microchip registry has its own coding system, and the fees vary. Veterinarians and shelters use hand-held scanners to detect the microchip and read the code. Then the appropriate registry is contacted and the owner notified. Though several companies produce the microchips, universal scanners can read all microchips.

Disadvantages of microchipping:
* The person who finds the dog may not know about microchips or where to take a dog to be scanned. (You should take a lost dog to a veterinarian or a shelter to be scanned.)
* When you move, you must remember to update your contact information with the registry.
* Because it is hidden, a microchip is not the most effective ID method if used alone.
Use in conjunction with collars and tags and/or tattooing to provide the most comprehensive protection.

Helpful Hints to Avoid Lost Pets
* Do not let your dog roam. Unleashed, unsupervised dogs are vulnerable to traffic, attacks from other dogs, theft, and abuse. Walking your dog on a leash and keeping him in a secure yard are simple ways to greatly reduce the chance that your dog will run off.
* Neuter or spay your dog. A neutered or spayed dog is less likely to wander.
* Take proper care of your dog. Provide him with a safe, comfortable home; feed, walk, and water him adequately; and give him plenty of love and attention. Well-tended dogs have less reason to stray.
* Just in case: Make sure you always have a current color picture of your dog and a record of her height, weight, coloring, and distinguishing marks. This information will make the search for a lost pet easier.