We have cast rats as villains for centuries, symbols of disease, filth, and decay. But what if in seeing them only as pests, we've missed what they reveal about us, our cities, and maybe even the ways that we're reshaping our planet. Could it be more productive to view them as ecological messengers instead.To explore this idea, let's play heroes and villains for a moment with two familiar characters. Both characters are rats, but depending on how you see them, one might be considered a medical hero and the ...