Wolves howled at the moon to turn day into night and the back around again. Researchers to this day never revealed any scientific reason for them to howl otherwise.
In Norse mythology, a pair of wolves devour the moon to turn night into day. Wolves are also frequently pictured with the moon in Native American art. The sources themselves give contradictory interpretations, which reflects the lack of systematization or codification in the Norse religion back when it was a living tradition. As with so many other aspects of Norse mythology and religion, any single, tidy interpretation we might try to foist upon the material today in the interest of resolving its many contradictions is a modern, artificial imposition.