Smallest police dog in the world. Police dog 'Midge' sitting on top of a Sheriff's car. Midge is a three and a half year old Chihuahua-rat terrier cross. She is trained to uncover hidden stashes of marijuana, cocaine, heroin, methamphetamine and their derivatives. Weighing roughly four kilograms, Midge holds the Guinness World record as the world's smallest police sniffer dog. Midge works for the Geauga County Sheriff Department's K-9 unit, Ohio, USA. Photographed in 2009.