Walking the Dog III

The saga continues and concludes (?).  (With, perhaps, one stanza too many.)

                                                             Walking the Dog III


                                       If my wife is right, who started the conversation?
                                      Was it some prehistoric proto-pup who left his mark
                                      when this suburban street was a Neolithic hunting
                                      trail of peers, when dog and master were newly met?

                                     And when will the conversation end, if ever?
                                     With some mutant mongrel staggering through
                                     a nuclear wasteland and emptying his glowing
                                     bladder one last time before he dies?

                                     Or will it wait until the ocean comes again
                                     and we are all left to dog paddle our way
                                     to some new and too distant shore?

                                    Perhaps, though, thousands of years from now
                                    a man and his dog will walk this same path,
                                    in whatever shape it’s taken by then,
                                   and the man will think these same thoughts,
                                   vaguely sensing they’ve been thought before
                                   and left the mark we humans leave each other.