Can animal behavior help “predict” the arrival of earthquakes? A new, comprehensive review paper, published in the Bulletin of the Seismological Society of America, says that the evidence is pretty insubstantial in this regard.
Don’t fret if you think that animals do, in fact, sense when an earthquake’s a-coming: it’s widely implied that they can. Indeed, throughout history, a massive cornucopia of critters, from dogs to silkworms, have been reported acting bizarrely some time before a major earthquake hits, although the mechanism by which each animal is seemingly sensing the forthcoming quake remains heavily debated.
This new statistical review, led by the GFZ German Research Center for Geosciences, took a good look at such claims. Looking at 180 peer-reviewed publications discussing abnormal animal behavior prior to earthquakes, the team established as best they could when in the earthquake sequence the strange behavior took place and what kind of observations of the behavior were made, among other things.
The reports came from 25 different countries, but most originated in New Zealand, Japan, Italy, and Taiwan, all of which are seismically highly active countries. Over 700 records of claimed “animal precursors” to 160 different quakes were assessed.
Their review featured case studies involving over 130 different species, and included elephants fleeing to higher ground, ants having a little freak out, and toads temporarily changing their migratory patterns. Forget dogs running around and barking – the range of supposed predictive behaviors is vast and bizarre.
Sometimes, animals reacted mere moments before an earthquake struck. Others were seen to alter their behavior for days or even weeks before and after the event took place. Some behaved oddly near the earthquake’s epicenter; others acted up hundreds of kilometers away.
This is by far the most detailed statistical analysis investigating the phenomenon to date, which is why it's significant that the team found no strong evidence whatsoever that animal behavior can indicate when an earthquake is about to hit.
The major problem here is that the majority of these reports are anecdotal, and anecdotal evidence doesn’t make for good science. In fact, the anomalous behaviors were often poorly defined and were only “noticed” retrospectively, after the quake took place.
Lead author Dr Heiko Woith, a geoscientist at GFZ, told IFLScience he had a few personal favorite anecdotes. “Before a 1969 earthquake in China, a tiger was ‘depressed’,” he said. “Another highlight is a report from Europe: ‘The situation was unusual because my dog did not behave unusual before the earthquake’,” one witness mused.
There were a few so-called time series – statistical assessments of behavior carried out over time – but even these were too small to be considered as serious evidence.
Another issue is that quakes don't occur in isolation but as part of sequences of varying magnitudes and timescales. Sometimes you get swarms of tremors – those temporally and spatially close to each other – and sometimes they're far more spread out. Plenty of fore- and aftershocks bookend the most powerful quake, the mainshock.
Asking whether animals can “predict” earthquakes or not depends on which part of the seismic shenanigans you’re matching up with their abnormal behavior.
As the paper notes, many anomalous behaviors cluster with foreshocks, “suggesting that at least parts of the reported animal precursors are in fact related to foreshocks.” Again, though, the evidence is very shaky.
Sure, animals can potentially detect seismic waves or related environmental alterations that may be imperceptible to humans, but again, this is hard to substantiate. What if these abnormal behaviors are connected to unrelated environmental or zoological changes instead?
In sum, without a long-term and statistically rigorous dataset, the already flimsy evidence for this zoological-seismological link is hard (if not impossible) to verify, so don’t buy into the longstanding hype.