I have written before about how miraculously designed our Moon is to make possible the existence of humans, advanced civilization, and certain important scientific discoveries.1 Now, new studies give us yet more reasons to thank God for the Moon.
The Moon is the second brightest object in the sky. It is so dim, however, compared to the Sun that it has no measurable impact on the daytime behavior of nonhuman animals. The only significant human impact I am aware of is how humans can use the daytime Moon as a compass. Mentally drawing a line that connects the horns of the crescent or quarter Moon to the horizon approximately indicates the south direction.
At night, the Moon is bright enough to partially illuminate one’s surroundings. During my youth, thanks to the light of a nearly full Moon, I was able to find my way, at night, out of a wilderness mountain park back to civilization. For millennia, farmers have taken advantage of the harvest moons (the full moons during September and October) to extend the reaping of their fields into the nighttime hours.
Recent field studies by biologists and ecologists have revealed the amazing design of the Moon’s luminosity, orbital period, and phases for optimizing the nocturnal well-being of both predator and prey animals. For decades, biologists had assumed that the brighter the Moon, the greater the predation risk for nocturnal animals. A field study of 59 different nocturnal mammals revealed that, generally, the opposite is true.2 Small nocturnal mammals forage more on bright moonlit nights when they can spot predators more easily. This effect is more pronounced for prey mammals whose primary sense is sight and most pronounced for prey animals possessing the highest sight acuity.
Another field study done in Serengeti National Park showed that the low nighttime illumination associated with a new moon increased the hunting success of lions.3 Consequently, lions expend much more energy hunting during a new moon than they do during a full moon.
Predators primarily targeting carrion focus their nighttime predation during full moon phases when it is easier for them to find carrion.4 Predators subject to predation by larger predators tend to focus their nocturnal hunting activity during full moon phases. And, the higher up on the food chain a predator resides, the more likely that predator will expend substantially more hunting energy during new moon phases.
None of these research papers explicitly concludes anything about the design of the Moon for Earth’s life. However, several such design features of the Moon are apparent.
The tidal locking of the Moon to Earth means that the phases of the Moon are regular and predictable. Animals can easily adjust their life cycles and behaviors to match the lunar cycle. The Moon’s orbital period of 29 days is not so long that large predators like lions would need to wait too long for the cover of maximum nighttime darkness to optimize their hunting success. On the other hand, the Moon’s orbital period is not so short that prey mammals lack the time they need for extended, relaxed nighttime foraging.
If the Moon were even slightly larger in diameter, slightly closer to Earth, or if it possessed a slightly more reflective surface, animals would find it difficult to sleep at night and large predators would be challenged to find and kill enough prey to stay alive and provide for their offspring. If the Moon were slightly smaller in diameter, slightly more distant from Earth, or if it possessed a less reflective surface, animals would find it much more difficult to forage at night and either would suffer greater predation or would need to expend too much energy attempting to avoid predators.
Because of the unique features of the Moon, the predator-prey relationships of Earth’s life can be optimized for the benefit of both prey and predators. We now have even more reasons to thank God for the many ways he designed the Moon for our benefit and the benefit of all life.