I thought only my dog Brownie had great sniffing power but here is RFID Sniffer which doesn't sniff bones rather it finds out whether objects are tagged are not. It's a simple analog circuit which can detect 13.56 MHz RFID tags deployed generally in case of bank cards, loyalty cards etc.

The kit comprises of professional quality circuit board and other components besides battery. The RFID Sniffer Kit comes with plastic sleeve with ziplock and lanyard with clip so that you can wear it around your neck and carry it along whenever you want to. It is available for €15 whereas the assembled version is available for €40 which also includes the shipping charges.