I've never thought about this despite both of my cats being chipped, to be honest. They came chipped from the breeders (all cat shelters have them chipped when

I've never thought about this despite both of my cats being chipped, to be honest. They came chipped from the breeders (all cat shelters have them chipped when leaving as well), and vets just scan the chip when they first see them. Until this thread I haven't been sure what would happen if the cat is actually lost and gets scanned at a shelter or vet after being found. Having just looked it up, I see that for cats there is a single organization which registers microchipped cats. Registration is free and highly encouraged by vets, shelters, and breeders. I'm going to check my cats' chip numbers tomorrow to make sure the info is up to date, but I imagine they're tied to my "person number", which would make it pretty easy for a vet to track me down if they're found. For dogs, an ID chip is apparently required by law; dogs and the human responsible for them are registered in a central register run by the Board of Agriculture. So at first glance luckily there doesn't seem to be too much confusion with registration databases in my area from what I can see.