A microchip only works if the registration does
The chip does not hold your phone number. It holds a number that points at a database entry — and that entry is only as good as the last time somebody updated it.
A microchip is a small transponder, about the size of a grain of rice, that sits under the skin between the shoulder blades. Passed over with a scanner it reports one thing: a number. Everything useful — your name, your address, your phone — lives in a registry, filed against that number.
Which means a chip can be working perfectly and still be useless.
The three ways it goes wrong
- It was never registered. Implanting and registering are two separate steps, and a chip implanted at a shelter or by a breeder is sometimes still registered to them rather than to you.
- The details went stale. People move house and change phone numbers far more often than they think about the chip. A number that rings out is no better than no number.
- Nobody knows which registry. There are several. If you cannot remember which one holds your animal's details, a universal lookup search will usually tell you which registry a given number belongs to.
Worth doing once a year
Find the chip number — it will be on the paperwork from when it was implanted, and any practice can scan and read it in a few seconds. Check the registry has your current phone number and a second contact who is not at the same address. That is the whole job.
What it is not
A microchip is not a tracker. It has no battery and no location; it only does anything when somebody finds the animal and scans it. A collar tag with a phone number on it is still the fastest way home, because a neighbour can read it without going anywhere. The chip is the backup for when the collar has come off.