The AirTag network requires other Apple devices to be nearby in order to register the location. The chip itself doesn't have any GPS capabilities. Ultimately it

The AirTag network requires other Apple devices to be nearby in order to register the location. The chip itself doesn't have any GPS capabilities. Ultimately it depends where your cat usually goes; if he's surrounded by people or hanging out around sidewalks chances are someone with an iPhone will walk by and automatically update his location. If he's in the forest or in rural areas without any tech nearby, AirTags won't help you until he gets back into civilization.