This story was originally published on The Conversation. It appears here under a Creative Commons license. I teach a course on New England witchcraft trials, and students always arrive with varying degrees of knowledge of what happened in Salem, Massachusetts, in 1692. Nineteen people accused of witchcraft were executed by hanging, another was pressed to death and at least 150 were imprisoned in conditions that caused the death of at least five more innocents. Each semester, a few students ask me about stories they have heard about dogs. In 17th-century…