Police have “successfully trained” squirrels to sniff out drugs, not for a hidden stash of acorns, along the border in southwest China. They are part of a squad of six Eurasian reds trained by Chinese police to do a job traditionally left to sniffer dogs. They have proved just as efficient at detecting illegal substances as their canine counterparts but their small size enables them to search places that dogs would not be able to reach. These include awkward spaces in warehouses or distribution centres, for example, as well as raised areas that are too high for dogs. The squirrels...