I once had a cat who ran away from home. After 2 years of him missing, he came home. The only reason he came home was because he had a microchip.
Anytime someone brings an animal into a veterinary clinic or animal shelter, and are told that the animal was found as a stray, the animal is always scanned for an identifying microchip.
If the pet is found to have a chip, the clinic or shelter employee can call the microchip company and get the owners contact information.
If you have an animal, it is a very good idea to have them microchipped.
Even if you think that they would never run away, strange and unexpected things happen.
What Is A Microchip?