By the light of the silvery Moon Jonathan Powell considers the natural world’s connection to the Moon and stars
The astronomer’s forum
Watching a crescent Moon slowly drift westward in the fading light of an evening sky may not be all that scientific, but it does serve as a reminder that perhaps we aren’t the only ones drawn to its movement across the heavens. Indeed, humankind is just one of many living things touched “By the Light of the Silvery Moon”, as Doris Day sang in the 1953 film of the same name.
The umbilical-chord existence that tethers Earth to the Moon is an incredibly strong bond, as both worlds duet their way around the Milky Way – a bond that’s absolutely crucial for so many species.
For the baby turtle after hatching amid the sand, the gaze of its freshly opened eyes focuses in on the moonlight reflected off the nearby sea, acting as a beacon to guide the turtle safely to the water’s edge. Interestingly, to the ancient Scots, Norse, Polynesians and Native Americans, the shell of a turtle was of enormous interest.
The shell, when viewed from above, was seen to comprise 13 major inner segments and 28 outer segments around the shell’s edge. These divisions were interpreted as 13 Moons and 28 days, the equivalent to 364 days plus one day of rest. No doubt you can buy a calendar with turtles on it today; but to them the turtle itself was a 13-month calendar, incorporating 13 Moon cycles a year, each made up of 27–29 days.
Turning to birds, the European nightjar’s migratory pattern is synchronised with lunar cycles. Aside from the Moon, most songbirds like thrushes and warblers migrate at night, choosing a single star like Polaris for guidance, gauging the movement of the constellations relative to the star, thus calculating the direction they need to be travelling. At night, the air is cooler and calmer too, meaning that birds use less energy on their long migratory journeys, with the added bonus that travelling under the cover of darkness means less predators.
