Frost turns the constellation Canis Major into a playful “Overdog,” a huge heavenly dog with a star for an eye that leaps up in the eastern sky and bounds all the way west without ever resting on its front paws. The motion is joyful and tireless, as if the night sky itself is romping. Then the speaker shifts to himself, calling himself “a poor underdog,” small and earthbound by comparison. But instead of feeling sorry for himself, he decides to join in: tonight he will bark along with the great Overdog moving through the dark.
The mood is whimsical and a little tender. There is affection for the night, for dogs, and for the idea that even a small, ordinary creature can feel connected to something vast and bright. It turns loneliness or insignificance into a moment of shared play.