No scientific study has proven that animals reliably predict natural disasters, but if your beagle starts losing it for no apparent reason, brace yourself.
There's enough anecdotal evidence of creatures freaking out and even fleeing areas en masse before earthquakes to take unusual animal behaviour seriously, as our gallery of dog-related tweets that followed today's 5.9 earthquake in D.C. suggests.
But there's nothing supernatural or sixth sense about it. Seismologists think animals sense an electrical signal generated by the movement of underground rocks before an earthquake. Or they might sense early but weak shocks that humans can't feel. Even the US Geological Survey concedes that animals likely perceive earthquakes sooner than humans:
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.
P or primary waves are seismic waves of energy preceding a tremor. They travel faster than S or secondary waves, which are the ones that cause damage during an earthquake. Some advance warning systems can detect P waves 60 to 90 seconds before shaking starts, kind of the way we see lightening before we hear thunder.
As for predicting a earthquakes days or weeks in advance, seismologists are more sceptical. One theory that lost pet ads in the San Jose Mercury news increased before earthquakes in the Bay Area was debunked by a statistical analysis published in California Geology in 1988.
Here's a quick sampling of animal weirdness anecdotes pre-earthquakes:
Before the devastation in Japan earlier this year, witnesses reported elephants and monkeys moving to higher ground as well as crazy behaviour in cattle, dogs and other domestic animals.
Before China's devastating 2008 earthquake, zebras banged their heads against doors, elephants swung their trunks wildly, lions and tigers paced when they should have been napping, and peacocks screeched simultaneously just five minutes before the tremors struck. Similar stories came from the Asian tsunami in 2005.
The problem is no one's been able to pinpoint a consistent animal behaviour that they can use as a disaster predictor. The connection doesn't seem to be reproducible. And of course sometimes your pet will simply nap pre-earthquake. From a Washington Post Q &A with
Earthquake expert Mike Blanpied from the US Geological Survey after a 3.6 tremor in Bethesda, Maryland, in July of last year:
Bethesda, Md.: How come my cats and dog did not react prior to or during the earthquake?
Mike Blanpied: Many animals responded to the shaking of the earthquake, because they are sensitive to even slight shaking. However, the earth did not give any indication that the earthquake was about to occur-although from time to time there have been claims of "animal earthquake prediction," it has never been demonstrated that animals have a special ability in this area. In fact, the earth may not give any warning at all!
In science, anecdotes alone can be dangerous and misleading. And scientists can't (at least not yet) use animal behaviour to recommend mass evacuations. But it would likely be harmless, and possibly save your life, to relocate to higher ground if you live near the ocean and your mutt flips and there's no clear reason why.