To me, this suggests that regardless of our understanding of their intellectual capacities, they are looking for visual cues from the Moon, which they evidently remember, and hold in great regard.
Equally interesting, is that sightless animals are far more regular and much more perfectly synchronized with lunar cycles- which clearly indicates that they are relying on senses beyond our current understanding, but which still have a powerful association to the pull of the Moon.
If you live in a neighborhood where many of the residents have dogs, you are never in doubt of when the moon is rising. Canines of all types greet the Moon with vocalizations, chilling and yet oddly harmonious.
This baying calls to something in our deepest and most primitive nature, and is evocative of a time long before indoor lighting and artificially sheltered environments, when keeping track of the cycles of the moon could mean the difference between survival and starvation.
I myself have seen deer move to the roadsides, to stand gazing at the open sky, where the moon sails majestically across the night- and I have seen the gleaming green eyes of tiny silver fish skimming the surface of the sea, gazing up at the horizon where the moon is about to appear.
The oldest artifacts known to be man-made depict the changing lunar cycles- evidence that our forebears did what they could to make sense of the variations they witnessed month after month.