If you have a cats that roams outside, beware of bunchers. Bunchers are thieves that trap and steal domesticated pets and sell them to laboratories to be experimented on: https://en.wikipedia.org/wiki/Buncher
An RFID microchip combined with a GPS collar (Pawtrack.com has a good one) may help prevent such a terrible outcome, but there are no guarantees.
An RFID microchip combined with a GPS collar (Pawtrack.com has a good one) may help prevent such a terrible outcome, but there are no guarantees.