Lunar and solar eclipses: what effects on the behavior of animals?
Most animals structure their day – in fact, their year – according to the cycle of light and darkness.
C are regular and rhythmic cycles during the day their dictate when to eat, sleep, migrate and mate.
The animals detect it from the number of hours of light that surrounds them. But lunar cycles also play an important role in their behavior.
The synodic period of the Moon – the time it takes to return to the same position, from full moon to full moon – causes changes in the earth’s magnetic field, the gravitational pull of the moon on the earth and light levels at night.
Several species detect it and use it to synchronize their mating.
Massive coral spawning frees tens of millions of eggs at once on coral reefs to coincide with the full moon or new moon. But what happens to animals when the Sun or the Moon behaves unusually or unexpectedly, as happens during an eclipse?
Among all cosmic events, it is solar eclipses that cause the greatest behavioral changes in animals. Those normally active during the day are so disturbed that they return to their nocturnal territory; the nocturnal animals think they have slept too much.
A solar eclipse occurs when the Sun and Moon are aligned in the same axis so that the Moon completely blocks the Sun. Across the planet, weird behaviors occur while people are busy watching the eclipse.
Some species of spiders begin to disassemble their web during an eclipse, which they normally do at the end of the day. Once the eclipse is over, they go back, probably upset by the lack of rest between the two operations. In the same way, the active birds and fish during the day will rest, while the bats leave, apparently deceived by the sudden darkness.
In Zimbabwe, hippos were seen leaving their rivers during an eclipse to the dry lands where they feed in the evening. Halfway, the eclipse was over and the hippopotamuses, failing in their efforts, seemed agitated and stressed during the rest of the day.
A lunar eclipse occurs when the Moon, Earth and Sun are closely aligned, the Earth positioned between the two stars. As the Moon passes directly behind us, the Earth prevents sunlight from reaching it, thus creating a reddish glow. As these “Blood Moons” occur only at the time of the full moon, it is difficult to distinguish the effects that the lunar eclipse has on the animals from the effects of a normal full moon.
According to a 2010 study, the Azara’s marmosets – nocturnal monkeys – in Argentina stopped feeding during a lunar eclipse, when their universe began to darken. They may have had difficulty seeing their food or feeling too destabilized to be able to move safely between trees.
About three times a year, a “super moon” appears. This phenomenon occurs when the full moon coincides with the perigee – when the point of the Moon’s orbit is at a minimum distance from the Earth. The distance varies during the month, because the orbit of the Moon does not form a perfect circle. During the perigee, the Moon is 46,000 kilometers closer to Earth than at the climax, the time when it is farthest from the earth.
In the “super moon”, the evening light levels are 30% higher than the lunar moment, and the moon appears bigger in the sky. In a recent search, geese responded to this “super moon” occurrence when they overwintered in southwestern Scotland. We installed devices on these birds to measure their behavior and observed that during the night of these “super-moons”, their heart rate and body temperature had increased, whereas in normal times they would have been more peaceful .
Geese did not react to “super-moons” when the moon was covered with thick clouds and the night was very dark. Like humans, it seems that the bright light has awakened them, and raises their heart rate and body temperature to prepare them to face the day.
The lunar cycle and we
For centuries, people have been fascinated by the relationship between the lunar cycle and human behavior. Many fables and legends are associated with it, like that of the werewolf mythical beast. It should come as no surprise that the term “lunatic” – from the Latin word “lunaticus”, meaning from the moon – was once used to describe people who were thought to be insane, mentally ill, unpredictable or distracted. that we find more appropriate terms from the 1930s.
It was believed that the lunar cycle influenced a range of strange changes to occur in a person’s physiology and that social behaviors such as birth rate, fertility, epilepsy, quarrels were also under its influence. There are still many people who believe that violent crime and general disorder increase at the time of the full moon.
A series of research conducted in the late 1980s found no connection between the lunar cycle and human behavior. The influence of the moon on us may well be legend, but the confusion it sows in animals is very real.