size of chip? they're tiny. dog owners typically have the vet "chip" their pet as a puppy. full-grown dog doesn't need a bigger chip.

Those chips need to be scanned from about 3cm away. If you want a locator tag, it needs to carry enough power to broadcast a signal a useful distance. Still, a microchip is handy if you're not sure if it's your tiger you found.

Those chips cannot track a dog's location