The earliest reference we have to unusual animal behavior
prior to a significant earthquake is from Greece in 373 BC.
Rats, weasels, snakes, and centipedes reportedly left their
homes and headed for safety several days before a destructive
earthquake. Anecdotal evidence abounds of animals, fish, birds,
reptiles, and insects exhibiting strange behavior anywhere
from weeks to seconds before an earthquake. However, consistent
and reliable behavior prior to seismic events, and a mechanism
explaining how it could work, still eludes us. Most, but not
all, scientists pursuing this mystery are in China or Japan.
We can easily explain the cause of unusual animal behavior
seconds before humans feel an earthquake. Very few humans
notice the smaller P wave that travels the fastest from the
earthquake source and arrives before the larger S wave. But
many animals with more keen senses are able to feel the P
wave seconds before the S wave arrives. As for sensing an
impending earthquake days or weeks before it occurs, that's
a different story.
A once popular theory purported that there was a correlation
between Lost Pet ads in the San Jose Mercury News and the dates
of earthquakes in the San Francisco Bay area. A thorough
statistical analysis of this theory, published in California
Geology in 1988, concluded that there was no such correlation,
Another paper published in a scientific journal in the U.S.
on this subject by a respected scientist in 2000 is summarized
The paper poses this question: Is it reasonable for a seismic-escape
behavior pattern to evolve, and can such a genetic system be
maintained in the face of selection pressures operating on the
time scales of damaging seismic events? All animals instinctively
respond to escape from predators and to preserve their lives. A
wide variety of vertebrates already express “early warning”
behaviors that we understand for other types of events, so it’s
possible that a seismic-escape response could have evolved from
this already-existing genetic predisposal. An instinctive response
following a P-wave seconds before a larger S wave is not a “huge
leap”, so to speak, but what about other precursors that may occur
days or weeks before an earthquake that we don’t yet know about?
If in fact there are precursors to a significant earthquake that we
have yet to learn about (such as ground tilting, groundwater changes,
electrical or magnetic field variations), indeed it’s possible that
some animals could sense these signals and connect the perception
with an impending earthquake.
However, much research still needs to be done on this subject. The
author suggests establishing a baseline behavior pattern that can
be compared with reactions of various environmental stimuli, and
then testing various potential stimuli in the laboratory. Of course,
the presence of these stimuli still needs to be researched with
regard to precursory phenomena preceding an earthquake, for if these
signals aren’t present in the environment before an earthquake, a
connection is irrelevant.