It has been said that animals usually exhibit strange behavior before an earthquake strikes. According to the United States Geological Survey (USGS), the earliest references date back to Greek times, around 373 B.C. Rats, weasels, snakes and centipedes reportedly left their homes and headed for safety several days before a destructive earthquake.
On August 23, the USGS measured an earthquake with a magnitude of 5.8 in Virginia, causing evacuations at the White House, the Capitol and parts of the Pentagon. It was reported that the quake could be felt throughout the Northeast and the mid-Atlantic.
According to the Center for Earthquake Research and Information (CERI), over 1 million quakes occur each year. The recent earthquake that was measured at 5.8 is considered moderate, meaning it causes some damage. About 1,000 earthquakes of that magnitude happen annually, according to CERI.
The USGS states that such anecdotal evidence exists regarding animals, fish, birds, reptiles and insects exhibiting strange behavior anywhere from seconds to weeks before an earthquake. It has been recorded that a fish in a high school biology lab in California would flip on its side before some earthquakes.
CERI states, however, that, since animal behavior is not earthquake-specific, changes in animal behavior may be the result of other events, and it is impossible to determine beforehand which factors caused changes in behavior. CERI also found that such behavior is inconsistent with seismic events, in that earthquakes can occur with no previous changes in an animal’s behavior.