What is a microchip?

The microchip is a tiny computer chip, about the size of a grain of rice, programmed with an identification number. The chip is enclosed in biocompatible glass and is small enough to fit into a hypodermic needle.
Once an animal is injected with a chip, it can be identified throughout its life with this one-of-a-kind number.

To learn more check out this great informational article at DVM360