id go with tatooing. all three of our pets have that... i dont really know that much about microchips but i dont think id ever want to put some metal thingy inside my pets body like that. and sides, in Sweden where i live EVERYONE knows of tattoing and thats where the police looks when they find a lost pet, but not many ppl know what microchips are! but then again you live in Canada so that might not be an issue there...