We associate rats with conditions of poverty, but rats are no fools: they sensibly prefer a well-heeled home to a poor one. What’s more, modern homes make a delectable environment for rats. “The high protein content that characterizes the more affluent neighborhoods is particularly enticing,” James M. Clinton, a U.S. health official, wrote some years ago in a public health report that remains one of the most compelling, if unnerving, surveys ever taken of the behavior of domestic rats. It isn’t merely that modern houses are full of food, but also that many of them dispose
