Any animal living nearby can find its way into a house occupied by humans – sometimes by mistake, sometimes because among animals, as among people, there are individuals who do senseless things. The neighbours may keep ball pythons, cockatoos or prairie dogs, and sooner or later one escapes and turns up on our balcony. On top of that, global trade and climate change keep bringing new species into our cities, and some of them settle happily into our homes. So what should we do when we spot small eight-legged creatures moving across the bathroom floor? Or when we find those persistent little moths in the kitchen cupboards?