Here in NYC, though we have a leash law, about 90% of the dog walkers on my morning commute let their dogs run free. Big ones I can deal with; they're more like battleships in that you can tell when they're coming about. But the little ones skitter all over the pavement, and owners are oblivious to this, deep into their coffee or cell phone conversation (who wants to talk at that hour?). I dread the day that I run over one of those; probably get sued. The rats are for the evening commute; I saw one that was approaching cat size the other night. They run tiptoe, but at least generally in a straight line. Squirrels are like the small dogs, making right angle turns constantly; maybe they're not as intelligent as rats.