Smarter than most humans
and certainly other animals...
As we took our walks around the neighborhood, of course other dogs would bark, some of them more insistently than others. Ace took this all in stride, usually ignoring them. However, I remember one dog in particular that charged the fence, yapping like crazy. As the dog continued to yap, Ace sauntered along until we got almost to the end of this dog's yard. Then he casually lifted his leg and "baptized" the other dog. As the other dog stepped back and shook his head--sputtering but quiet--Ace resumed his sauntering. I don't recall that dog ever being out again when we walked by. :)