forms of bias influenced our data. What is evident, however, is that a substantial number of people believe that they have witnessed abnormal animal behavior prior to an earthquake.
Comparison of Animals and Behaviors
Dogs were the animal most frequently sited as behaving unusually prior to an earthquake. This is an especially interesting finding considering that there were more cat than dog owners in the study, and a previous survey of this same population found a correlation between this higher number of cat owners and a greater number of believers in “psychic” cats than dogs (Brown and Sheldrake, 1997). This finding of more “psychic”
cats had been somewhat counterintuitive as, in general, dog owners tend to have closer relationships with their pets than cat owners, and cats tend to be less sociable and more independent than dogs (Hart, 1995).
Unusual behavior is difficult to define, and determining if there is a characteristic behavior is not clear-cut, although there are some distinct patterns. For example, an intense fear that appears to make some animals cry and bark for hours, and others flee in panic has been reported often. Equally characteristic is the apparent opposite effect of wild animals appearing confused, disoriented, and losing their fear of people (Tributsch, 1982). Since there is experimental evidence that charged ionic particles can effect neurotransmitter ratios in animal brains, and that charged ions may be released prior to some earthquakes, it has been suggested that this may explain these two seemingly-contradictory behavior patterns (Tributsch, 1982).
In addition to the stories collected from the respondents in this survey, the authors of this paper have been collecting dozens of detailed accounts of unusual animal behavior prior to earthquakes through requests in newspapers and magazines, as well as on radio stations and internet sites.
Many people reported dogs vanishing or barking uncontrollably. A number of pet owners found their ordinarily calm cats suddenly darted off and hid, or paced around crying for a few minutes before the earthquake.
There were reports of goats and horses leaping around wildly, noisy birds suddenly becoming silent, or a whole flock of seagulls taking off all at once just before an earthquake. A few people noticed the number of roadkill increasing for several days before an earthquake. Although it’s primarily accounts of dogs and cats that have been reported, many other types of animals in the wild, on farms, and in zoos; including horses, cows, goats, possums, rats, chickens, and other birds have been observed acting in unusual ways.
Possible Explanations for the Unusual Behavior, and Why More Research into the Extraordinary Abilities of Animals is Necessary
The anecdotal evidence presented in this paper does not necessarily imply the existence of earthquake prediction abilities in animals. Some of the mysterious behavior discussed in this paper may ultimately be explainable in terms of reactions to ordinary stimuli. People may sometimes misperceive or exaggerate an animal’s abilities, and the anticipatory behavior may be projected upon them in retrospect. However, some of the unusual behavior discussed in this paper may be due to a genuine sensitivity to precursory earthquake signals, and when these results are combined with the results of previous studies and observations, a very strong case can be made for the existence of this phenomenon.
In the case that animals are actually reacting to precursory earthquake signals, the following explanations have been proposed:
1. Because many animals possess auditory capacities beyond the human range, it has been suggested that some animals may be reacting to ultrasound emitted as microseisms from fracturing rock (Armstrong, 1969).
2. Fish have a high degree of sensitivity to variations in electric fields, and because telluric current variations have been noted before some earthquakes, it has been suggested that this is what the fish may be reacting to (Ulomov and Malashev, 1971).
3. Because some animals have a sensitivity to variations in the earth’s magnetic field (usually as a means of orientation), and since variations in the magnetic field occur near the epicenters of earthquakes (Chapman and Bartels, 1940), it has been suggested that this is what the animals are picking up on (Otis and Kautz, 1985). Marsha Adams, an independent earthquake researcher in San Francisco, claims to have developed sensors that measure low-frequency electromagnetic signals which allow her to predict earthquakes with over 90% accuracy, although this remains to be substantiated. Adams suspects that low-frequency electromagnetic
signals– created by the fracturing of crystalline rock deep in the earth along fault lines– are “biologically active”, and that her instruments are picking up the same signals that sensitive animals do (Brown, 1997).
4. Some organisms respond to changes in the polarity and concentration of atmospheric ions, and it has been suggested that this sensitivity enables some animals to detect the air-ionizing effects of radon released from the ground in advance of certain earthquakes. (Ulomov and Mavashev, 1967). Tributsch has suggested that a piezoelectric effect may be at work here. On the average, the earth’s crust consists of 15% quartz, and in certain areas it can be as high as 55%. According to Tributsch, the piezoelectric effect of the quartz is capable of generating enough electrical energy to account for the creation of airborne ions before and during an earthquake. This electrostatic charging of aerosol particles may be what the animals are reacting to.
Animals, also observed acting unusual in similar ways prior to thunderstorms, may have evolved a sensitivity to electrical changes in their environment (Tributsch, 1982).
5. The effects of radon gas on the level of air ionization explained above, can also be expected to change the field gradient, and dozens of animals have been shown to be sensitive to changes in the electric field gradient of the atmosphere (Chalmers, 1967).
6. The animals may be perceiving and responding to stimuli that currently science has no way to measure.
Experiments that can help us decide between these explanations are not easily performed, as studying earthquakes has inherent difficulties, because they are infrequent and unpredictable by their very nature.
However, further investigation in this area could help us discover what the animals are reacting to, and to allow us to build sensors to detect the earthquake precursory signals. We suspect that these types of investigations hold enormous potential for understanding animals better, and predicting earthquakes more reliably. If an understanding of what animals are reacting to were to be obtained, it’s value would be tremendous.
However, even without understanding what the animals are reacting to, it is conceivable that an earthquake warning system could be created by networking people who observe animal behavior on a routine basis– as Kautz and Otis did with Project Earthquake Watch, and the Chinese and Japanese have practiced for hundreds of years. Even something as simple as tracking the number of missing animals may prove to have some predictive value with regard to earthquakes. Retired USGS geologist James Berkland claims to be able to predict earthquakes with over 75% accuracy, in part through calculating the number of lost pet ads in the newspaper each day. (Brown, 1996).
The pool of untapped resources potentially residing right under our noses may be vast. There are between 51 and 58 million households in the U.S. with dogs, and 49 and 60 million households with cats (American Demographics, 1991). [Rupert– I am in the process of obtaining statistics for California.] This huge untapped and easily accessible population of potentially geophysically-sensitive animals may be holding an enormous wealth of information.
Animal experiments in this area hold great promise. Although studying the possible relationship between earthquake precursors and animal behavior may prove challenging, utilizing the animals’ apparent sensitivity to precursory signals may not be difficult, and the benefits could be enormous. When one considers the annual and historical devastation wrought by earthquakes in the form of lives, property, and valuable resources, it becomes increasingly clear why studying this apparent sensitivity in animals is so vital.
We would like to thank all the people who took part in this survey, as well as Pamela Smart, Nina Graboi and Ralph Abraham for their valuable contributions.
David Jay Brown
P.O. Box 1082
Ben Lomond, California