For Temnothorax ants in search of suitable rock crevices for new nest sites, size is an important consideration, and certain behaviors suggest how scouts might compare the size of several sites. After entering a crevice, scouts invariably exit and reenter. During their first inspection, they mark their route with their personal pheromones. (Experiments have shown that workers can distinguish their own pheromones from those of nest mates.) Some researchers believe that these ants are counting the frequency of intersections between their two exploratory trails. The smaller the area, the more likely they are to cross a spot twice. The observation that Temnothorax scouts always pave out a path of the same length on their first visit to sites strongly supports this hypothesis.