Want monthly animal activity charts to go?
Find them in The Nature Almanac!Only $5.95 (cheap!) For more info, or to order, click About our book
Animals and the Moon
About our book,
Including monthly animal activity tables for 2005
Do animals respond to the influence of the Moon?
The short answer is yes, they do, and science has recorded thousands of examples showing a positive correlation between animal behavior (this includes human behavior) and the moon. Science however has not explained the mechanism that triggers this behavior; or more simply exactly how the moon causes this influence.
Back in the 1920's a fellow named John Alden Knight attempted to predict the activities of animals based on the positions of the sun and moon. In an interesting, but frustratingly vague, book Moon Up - Moon Down he detailed the story of his discovery of this phenomenon without revealing his methods for determining it. He named his hypothesis the Solunar Theory and annually published small pamphlets, The Solunar Tables, that predicted the activity periods for every day of the coming year.
In a nutshell his theory was that when the moon passes directly overhead (Moon Up) or directly beneath the observer (Moon Down) animal activity was greatest - and hunting, fishing, and observation of animals most fruitful. He found that the sun's position relative to the moon also played a role and retarded or accelerated the time of activity, or what he called the Solunar Period. What he was actually predicting were the periods of high tide for any given place on earth. Having used his Solunar Tables for several years I can say that they work, after a fashion, and are well worth the modest price for any serious hunter or fisherman who cares to invest in a copy.
When the Snakes Awake
Now while I found all this prediction stuff extremely interesting, and even useful, I was far more interested in how it worked - the mechanism that triggered it - than when it worked. I believe I've found the answer in another, even more obscure but utterly fascinating book When the Snakes Awake by Helmut Tributsch, a geologist interested in earthquake prediction.
Dr. Tributsch was interested in why animals seemed to be able to predict the arrival of earthquakes minutes, hours and even days, before they occurred. He collected a huge number of examples of this phenomenon stretching back thousands of years and on every continent. He also enumerated and explored a large number of little known and unexplained phenomena associated with earthquakes (earthquake lights, fogs, lightning, noises and electrical phenomena) in an attempt to find a common denominator both for the earthquake effects and their effect on animals
His conclusion was that just before the actual earthquake proper, the rock layers are under extreme stress due to compression, bending and stretching of the strata. This stress causes the silica in the rocks to release electrons due to the well known piezoelectric effect on quartz crystals. These electrons both liberate hydrogen and oxygen by splitting water molecules due to electrolysis and also form large numbers of highly active ions which are expelled from the ground just prior to the earthquake.
His hypothesis is that it's these ions that excite and disturb the animals. The beauty of his theory is that these ions explain why fish in water, animals on land, birds in the air, and even animals locked in the equivalent of Faraday cages (a device used to isolate a given volume of space from all electrical effects) would react strongly just before an earthquake hits. Professor Tributsch's theory remains just that, a theory, but so far it's the best theory out there and the only one that fits all the data.
Synthesis of tides and ions
The relevance of his theory to daily animal activity periods wasn't immediately apparent after I read it, but the ideas and the data he presented sort of percolated around in the back of my mind for a number of years. It wasn't until I began researching the Moon Gardening section for this Almanac (and began discovering the vast literature on lunar effects on earth's organisms) that all the pieces fell into place. The explanation I've come up with incorporates Knight's tidal theory and Tributsch's work on earthquakes.
As I never tire of telling people, the moon causes tides in more than just the oceans of our planet. There are atmospheric tides, groundwater tides, tides in the magnetosphere and earth tides. When the moon is directly overhead you're about two feet closer to our orbiting satellite than when the moon is at right angles to you. This rise and fall of the earth beneath our feet happens twice each day. The only reason we don't notice it is that it rises gradually and occurs over thousands of square miles simultaneously. And it affects the entire planet down to the core.
Now while this tidal deformation of the crust isn't as extreme as that produced by an earthquake, it is enough to cause silica in the crust (the most abundant element there) to be deformed and release some electrons (which create ions) twice each day. This, coupled with the exhalation of these ions by the rising groundwater tides, would propel a small but significant number of ions into the atmosphere from the earth. And it's these ions, I believe, that animals sense and which signal them into their tidally regulated activities each day.
Of course some animals, oysters for instance and several corals, actually respond to lunar gravitation. It could well be that all animals (including us) respond to fluctuations in gravity, but based on animal behavior during these activity periods I believe that there is more at work than mere response to lunar gravity. Based on both personal experience and the reports of a large number of observers, smaller animals react more quickly to lunar tides than larger ones. Were they all reacting to merely gravitational cues one would expect all creatures to react simultaneously regardless of size. Since size does seem to matter and since this theory predicts that smaller animals which would collect electrical charge and reach electrical equilibrium more quickly than animals with a larger volume (and hence larger electrical capacity) I believe this to be the true explanation of how and why the moon affects living organisms.
And while no one should take this explanation as gospel (it is just a theory after all and untested at that) it is an interesting explanation for a well known phenomenon and something to ponder the next time you cast into a small bay for bass. As for the testing.... well, any interested grad student looking for a thesis topic can contact me anytime for further information
Copyright © 2004 Jim Jung