Sometime during or just after the Civil War, a black rat in Williamsburg, Virginia, came into possession of a rare trophy: a solid silver fork. The rodent—a member of the ubiquitous species Rattus rattus, which arrived in North America with the Jamestown colonists—was living between the walls in a building that had variously been a home, a shop, a school, and a popular tavern. The rat’s family had likely been there for generations, gradually adding scraps of paper, fabric, crockery, bones, and miscellaneous debris to its massive nest. Pilfering the…