Yeah, really interesting point and I appreciate all the examples you included—I will have to read more on those. I’ve similarly been intrigued by the common belief that dogs “mark their territory.” It downplays the significance of using urine as a language. What seems more accurate, IMO, is that dogs use urine as a mode of asynchronous chemical communication. With the Jacobson’s organ, they can get all kinds of details by sniffing a lamppost. Is this a high traffic area, are the other dogs healthy, male or female, any potential mates, rough age, rough time (based on how old the urine smells), … it’s a spectrum of information.

Sometimes I wonder if my dog might recognize others, without ever having physically met them, because he’s been communicating with them via the fire hydrant for years. Not sure how likely that would be, but it’s certainly crossed my mind.