Dogs are amazing creatures, and some of their skills seem almost supernatural. Of course, it isn’t magic that gives dogs their extra-special abilities; they are simply able to sense things outside human perception. For example, they can smell odors and hear high-pitched noises undetectable to us. Is it possible that those super senses can help them predict earthquakes, too?
As far back as 373 B.C., there have been reports of animals behaving strangely in advance of an earthquake. You’ve likely heard anecdotal evidence that dogs act in unusual ways anywhere from seconds to days before an earthquake strikes. However, there is no conclusive scientific evidence that dogs can predict tremors, and nobody is certain of the mechanism they could be using to do so.
One possible method of early earthquake detection is sensing P waves. All earthquakes produce different waves that travel out from the earthquake’s source. A P wave is a compressional wave that shakes the ground in the opposite direction the wave is moving. It travels faster than the larger S wave, or shear wave, that shakes the ground in a direction perpendicular to the wave. Most humans don’t notice the smaller P wave, which, due to its faster speed, arrives seconds before the S wave. Dogs, with their sharper senses, might be noticing that P wave and reacting before humans realize anything is wrong.
Although that could explain a dog’s ability to sense danger within seconds of an earthquake, it doesn’t support the idea that they can alert to a quake hours or even days ahead of time. Could they be detecting other early signs, such as the ground tilting, or changes in the earth’s magnetic field? One likely possibility is that dogs are hearing the high-pitched, underground seismic activity of rocks grinding and scraping together that happens before an earthquake.
A study by Dr. Stanley Coren supports this suggestion. Dr. Coren was researching whether dogs can have Seasonal Affective Disorder when, by chance, he collected data the day before a level 6.8 earthquake hit the Pacific Northwest. His data included activity and anxiety levels in 200 dogs living in Vancouver, Canada, a city that was affected by the quake. On the day before the earthquake, 49 percent of the dogs showed a significant increase in anxiety, and 47 percent were considerably more active. This was a sharp increase from the steady day-to-day averages collected to that point.
The coming earthquake seems the most likely explanation for the changes in the dogs’ behavior. But what were they sensing? Dr. Coren suspected they were hearing seismic activity, so he dove into the data for more information. Fourteen of the dogs in his study had hearing impairments, and all but one of them did not show the increased activity and anxiety of the other dogs. Perhaps they were unable to detect what was bothering their fellow canines. Interestingly, the one hearing-impaired dog that did respond with anxiety lived with a dog that could hear normally, so may have been reacting to a change in his housemate’s behavior.
Dr. Coren also looked at ear shape because earflaps, like those seen in floppy-eared dogs, partially block incoming sounds. He divided the dogs in his study into those with prick ears and those with floppy ears. The dogs with prick ears showed more increase in activity and anxiety the day before the earthquake than those with floppy ears, possibly because they were able to hear more of the seismic activity.
To further explore the idea that the dogs were hearing high-pitched sounds, Dr. Coren grouped the dogs in his study according to the size of their heads. Mammals with smaller heads can hear higher frequencies better than mammals with larger heads, so those dogs with smaller heads should have sensed more of the earthquake predictor sounds. In fact, the dogs with the smallest head sizes tended to show a far greater increase in activity and anxiety levels before the quake compared to the dogs with the largest head sizes. This provides further potential evidence that it’s high-frequency seismic sounds that are alerting dogs to an upcoming earthquake.
Even though Dr. Coren’s research is only one study involving only one earthquake, together with the anecdotal evidence, it appears that dogs may be able to predict earthquakes, at least under the right conditions. If a quake produces loud enough high-frequency sounds in the days before it strikes, dogs may be capable of sensing that something out of the ordinary is happening.