Courtesy of Sue Johnson
Microchips are used for permanent identification. The chip is the size of a grain of rice and is actually a tiny computer chip that is encased in a glass material.
The chip can be read with a handheld device that uses radio waves to read the chip. Some microchips have been known to migrate so I have found that the best place to insert the microchip is in the tail web (the loose, hairless area under the tail on either side of the anus). I always use the left side of the tail web to make finding the microchip easier.