The glowing orb that lights our night sky does more than just create romantic backdrops and influence ocean tides. Our moon plays a surprisingly intricate role in orchestrating the behavior of animals across the planet, from the tiniest marine creatures to massive mammals roaming the African savanna. Scientists have been uncovering these lunar connections for decades, revealing patterns that challenge our understanding of how animals navigate their world.
The relationship between moon phases and animal behavior stretches far beyond folklore and superstition. Recent discoveries reveal how lunar light influences lion prey behavior, dung beetle navigation, fish growth, mass migrations and even birdsong. The moon’s light influences lion prey behavior, dung beetle navigation, fish growth, mass migrations and birdsong. These connections operate through complex biological clocks that have evolved over millions of years, creating synchronized behaviors that can be observed on a global scale.
Whether it’s zooplankton rising to feed under the Arctic moon or coral spawning in spectacular underwater fireworks, the lunar cycle serves as nature’s ultimate timekeeper. Let’s explore how moonlight shapes the secret lives of animals in ways that will surprise you.
Predators and Prey Dance to Lunar Rhythms
The African savanna transforms into a different world when the moon rises. Lions of the Serengeti in Tanzania are night stalkers. They’re most successful at ambushing animals (including humans) during the darker phases of the lunar cycle. Lions of the Serengeti in Tanzania are night stalkers. They’re most successful at ambushing animals (including humans) during the darker phases of the lunar cycle. This ancient game of survival reveals one of the most dramatic examples of how moonlight influences the predator-prey relationship.
Meredith Palmer, an ecologist at Princeton University, and colleagues spied on four of the lions’ favorite prey species for several years with 225 camera traps installed across an area almost as big as Los Angeles. Volunteers with the citizen science project Snapshot Serengeti analyzed thousands of images of these animals. The results painted a fascinating picture of how prey animals adjust their behavior based on lunar phases.
The routines of plains zebras (Equus quagga) and Thomson’s gazelles (Eudorcas thomsonii) also changed with the lunar cycle. But unlike the other prey, these animals reacted more directly to changing light levels across the evening, Palmer says. Gazelles were more active after the moon had come up. Zebras “were sometimes up and about and doing things before the moon had risen,” she says. That may seem like risky behavior, but being unpredictable could be a zebra defense strategy to keep lions guessing, she says.
Ocean Migrations Follow Lunar Schedules
Far beneath the Arctic ice, an extraordinary migration unfolds every night, guided not by the sun but by the moon’s gentle glow. Normally, those migrations by krill, copepods and other zooplankton follow a roughly circadian (Sur-KAY-dee-un) – or 24-hour – cycle. The animals descend many centimeters (inches) to tens of meters (yards) into the ocean around dawn. Then they rise back toward the surface at night to graze on plantlike plankton. Yet during the dark Arctic winter, something remarkable happens.
But winter trips follow a slightly longer schedule of about 24.8 hours. That timing coincides exactly with the length of a lunar day, the time it takes for the moon to rise, set and then begin to rise again. And for about six days around a full moon, the zooplankton hide especially deeply, down to 50 meters (some 165 feet) or so. This behavior suggests these tiny creatures possess internal clocks finely tuned to celestial mechanics.
When the winter moon is full over the Arctic, it stays above the horizon for a handful of days (depending on latitude), and during this time, zooplankton dive to take cover from predators. But while the moon is out, it also rises and sets – and the zooplankton respond, rising and diving over the course of this cycle, which takes 24 hours and 50 minutes. This discovery reveals how moonlight can substitute for sunlight in driving biological rhythms.
Birds Time Their Journeys by Moonlight
The nocturnal world of bird migration holds some of the most remarkable examples of lunar influence on animal behavior. Tracking of the nightjar, a long-distance nocturnal migrant bird, reveals that it adjusts its movements in relation to the lunar cycle. Based on an intensive study of 38 birds monitored for one year or less, the authors conclude that, by allowing birds to fuel their body reserves, the lunar cycle drives migration patterns of this nocturnal bird, with a high synchrony of migration movements about 10 days after a full moon event.
We found that the daily foraging activity more than doubled during moonlit nights, likely driven by an increase in light-dependent fuelling opportunities. This resulted in a clear cyclicity also in the intensity of migratory movements, with occasionally up to 100% of the birds migrating simultaneously following periods of full moon. This synchronization creates waves of migration that can be observed across entire continents.
The European nightjar isn’t alone in its lunar dependency. The occurrence of birds increased with moon fraction, moonlight intensity and duration, while abundance correlated positively with increasing moonlight intensity. The occurrence of birds increased with moon fraction, moonlight intensity and duration, while abundance correlated positively with increasing moonlight intensity. These patterns challenge previous assumptions about nocturnal migration strategies.
Marine Spawning Spectacles Under Full Moons
One November night each year, the ocean comes alive in what can only be described as nature’s most spectacular fertility festival. One November night each year, beneath the full moon, more than 130 species of corals simultaneously spawn in Australia’s Great Barrier Reef. But most release both eggs and sperm, packed together in round, buoyant bundles as small as peppercorns and blushed in shades of pink, orange, and yellow. Then, in stunning unison, numerous corals lose their seeds, which hover momentarily above their parents, preserving the shape of the reef in an effervescent echo.
Many reef-building corals participate in a mass-spawning event that occurs yearly on the Great Barrier Reef. This coral reproductive event is one of earth’s most prominent examples of synchronised behavior, and coral reproductive success is vital to the persistence of coral reef ecosystems. During these annual events changes in the intensity of moonlight trigger the spawning of more than 130 species of scleractinian corals as well as hundreds of other invertebrates over a couple of nights.
Here we present a synchronized spawning mechanism that the appearance of a dark period between sunset and moonrise is the cue to trigger spawning in coral D. speciosa. In other words, moonrise timing is the key factor to synchronize spawning. This precision timing ensures maximum fertilization success in the vast ocean environment.
Nocturnal Hunters Navigate by Celestial Light
In the darkness of night, some of nature’s most skilled navigators rely on an unexpected compass: moonlight itself. For nocturnal dung beetles, moonlight is a compass. How well the insects navigate depends on the phases of the moon. These industrious insects demonstrate remarkable precision in using lunar cues for orientation during their nighttime activities.
The phenomenon extends beyond simple navigation to complex behavioral adaptations. The UV rays of moonlight react with a protein in scorpions that makes them glow in the dark. These arachnids seem to react to glowing the way that people react to blushing: the brighter the signal, the deeper they try to retreat. They tend to be more active during the new moon, and seek shelter later in the lunar cycle. Researchers are still not quite sure why this is, but some suggest prey may be more available during darker nights. And with less prey roaming about during the full moon, the scorpions shy away from the spotlight.
Doodlebugs dig new traps every day, and researchers have found that these holes get bigger during full moons. This surge in hole size may be the result of their insect prey becoming more active under the light of the full moon, making the extra effort of digging larger holes pay off. However, researchers have found that this habit persists even within complete darkness of a laboratory, suggesting that other components of the lunar cycle play a role as well.
Fish Reproduction Cycles Match Lunar Phases
Beneath the waves, fish species across the globe have evolved sophisticated timing mechanisms linked to lunar cycles. Now, beyond the tides: light from the moon makes it easier for young fish to spot their zooplankton prey at night. On the flip side, it also makes it harder for predators to sneak up on prey. This double-edged effect of moonlight creates complex behavioral responses in marine ecosystems.
Because many predators in coral reefs hunt by sight, a cover of darkness may give young sixbar wrasses the best chance of settling into a reef undetected. In fact, Shima has shown that some of these fish appear to stay at sea several days longer than normal to avoid a homecoming during the full moon. Moonlight might similarly influence larvae of many kinds of reef fish and affect many aspects of the life cycle, Shima says.
Migrating chum salmon swim more quickly and at shallower depths during a full moon, likely because they are using its light as a lodestar. Newborn rabbit fish seem to depend on moon phases to reach safety: on the day before or during the new moon, when the sea is darkest, rabbit fish fry born in the open sea migrate en masse to the haven of coral reefs. These behaviors showcase the intricate timing mechanisms that have evolved in marine environments.
Amphibian Activities Follow Moon Patterns
The primary reasons for changes in amphibian behavior in response to the lunar cycle appear to be temporal synchronization of breeding and predator avoidance. The primary reasons for changes in amphibian behavior in response to the lunar cycle appear to be temporal synchronization of breeding and predator avoidance. Responses to changes in prey availability, facilitation of visual signalling and use of lunar cues in navigation and homing are less prevalent but merit further investigation. These ancient vertebrates show some of the most diverse responses to lunar influences.
We found that there is no significant difference between the numbers of species which increase, and those that decrease activity or reproductive behavior (including calling) during a full moon. The responses to the lunar cycle can not be generalized across taxonomic group, but instead are highly species specific and relate directly to the species’ ecology. This variability highlights the complex evolutionary pressures that have shaped lunar responses in different environments.
European badgers reportedly tend to raise their leg up when they pee more often during the new moon (when the moon is between the Earth and sun so the side facing us receives no direct sunlight) than the full moon, researchers have found. And the new moon seems to be prime time for badger mating, with scientists suggesting the increased darkness provides the badger couple protection from lurking predators. Pairs of badgers can reportedly take up to 90 minutes to mate, and become easier targets during that time. So while the pee pattern may seem to be a loony habit, it appears to have a practical root in self defense.
Reptilian Responses to Lunar Cycles
Most reptiles are active during daytime; there are very few studies on the effect of Moon phase on reptiles. Most studies found that snakes are less active during full Moon nights, among them a small cryptic desert snake, the desert nightsnake (Hypsiglena chlorophaea), which feeds on other small reptiles, the habu (Trimeresurus flavoviridis), a venomous pit viper species endemic to the Ryukyu Islands of Japan, and the fish eating snake Lake Tanganyika water snake (Lycodonomorphus bicolor). Bright moonlight avoidance by snakes may be a strategy that reduces detection by visually hunting predators and may also be influenced by the activity patterns of their nocturnal rodent prey.
The patterns vary significantly among different reptilian species based on their ecological niches. A different response was observed in the Florida cottonmouth snakes (Agkistrodon piscivorus conanti) which are terrestrial, and feed on fish carrion dropped by nesting birds. This variation demonstrates how evolutionary pressures have created diverse strategies for dealing with lunar light exposure.
The Future of Lunar-Influenced Behavior
As our planet becomes increasingly illuminated by artificial light, scientists are growing concerned about the disruption of these ancient lunar rhythms. Furthermore, our results from both experiments on the effect of ‘light pollution’ on coral spawning behavior suggest that disruption or phase shift delay in spawning time can occur rapidly, that is, within 7 days of exposure to changes in nocturnal light regimes. The interplay between endogenous clocks and external cues in an era of industrialization and global change (when artificial lights compete with moonlight to affect reproductive timing and fertilization success in broadcasting species) should be considered in plans to protect coral reefs and marine ecosystems.
Researchers are worried, too, about the fate of spectacular synchronized events like coral spawning in a light-polluted world. If coral clock mechanisms are similar to the bristle worm’s, how would creatures be able to properly detect the natural full moon? In 2021, researchers reported lab studies demonstrating that light pollution can desynchronize spawning in two coral species – Acropora millepora and Acropora digitifera – found in the Indo-Pacific Ocean. Shlesinger and his colleague Yossi Loya have seen just this in natural populations, in several coral species in the Red Sea.
The challenge extends to terrestrial environments as well. Artificial light at night disrupts the natural behaviors of migratory birds, monarch butterflies, and even the plants they depend on. Birds and monarchs rely on their internal clocks, guided by natural light cues from the stars and moon, to navigate migration. Exposure to artificial light at night can cause disorientation, leading to exhaustion, premature migration, or even tragic collisions.
The moon’s influence on animal behavior represents one of nature’s most elegant timing systems, refined over millions of years of evolution. From the synchronized spawning of corals to the migration patterns of Arctic zooplankton, these lunar connections reveal a hidden layer of complexity in the natural world. Yet as human activities continue to alter the nighttime environment, we risk disrupting these ancient rhythms that countless species depend upon for survival and reproduction. Understanding these lunar influences isn’t just fascinating science, it’s crucial for conservation efforts in our increasingly illuminated world. What other secrets might the moon be whispering to the creatures that share our planet?
