Oreo, a Boston terrier, went missing from his owner's yard more than four years ago, the Palo Alto Daily News reported.
The Peninsula Humane Society and Oreo's owners say the dog and his family were finally reunited largely because of a microchip that was implanted under Oreo's skin. The device was encoded with his family's contact information.
Oreo was found Tuesday wandering near the Security Public Storage in Daly City, and the microchip was detected during an exam at the Humane Society in San Mateo, officials said.
"To get a dog back that you thought was gone for good is pretty crazy," said Brandon Springer, adding Oreo belonged to his grandmother, Ann Guglielmelli, who died last May. "It shows that it does work."
"This story illustrates the importance of microchips, which can be a lost pet's ticket home," said Scott Delucchi, a spokesman for the Humane Society. "Too many people don't know how inexpensive this can be and how easy of a process it is. Hopefully, this happy ending will cause more people to consider this permanent form of identification for their pets."