A video posted to Twitter and Reddit reportedly shows birds acting strangely prior to the earthquake which hit Turkey and Syria on Monday.
The video is as yet unverified and there are of course reasons to be skeptical of it (think about how after every flood disaster, someone claims that a shark has made its way down the highway of a major city).
But can animals genuinely sense earthquakes before humans (and human equipment) know it's coming?
The idea that they can is not new, and dates back at least to 373 BCE, when Greek historian Thucydides wrote that dogs, rats, snakes, and weasels deserted Helice days ahead of a deadly earthquake that hit the city. Other anecdotes from history have claimed animals behaved strangely prior to earthquakes too.
"Some minutes before they were felt, the oxen and cows began to bellow, the sheep and goats bleated, and, rushing in confusion one on the other, tried to break the wicker-work of the folds; the dogs howled terribly, the geese and fowls were alarmed and made much noise; the horses which were fastened in their stalls were greatly agitated, leaped up, and tried to break the halters with which they were attached to the mangers; those which were proceeding on the roads suddenly stopped, and snorted in a very strange way," one account of the Naples quake of 1805 reads.
"The cats were frightened, and tried to conceal themselves, or their hair bristled up wildly. Rabbits and moles were seen to leave their holes; birds rose, as if scared, from the places on which they had alighted; and fish left the bottom of the sea and approached the shores, where at some places great numbers of them were taken."
The account goes on to say that ants and reptiles abandoned their homes, while locusts flew through the streets.
"Some dogs, a few minutes before the first shock took place, awoke their sleeping masters, by barking and pulling them, as if they wished to warn them of the impending danger, and several persons were thus, enabled to save themselves," the account adds.
However, the problem with anecdotes like this is that they are anecdotes and they rely on people retroactively noticing the strange behavior of animals after the earthquake has happened. Scientists, of course, have looked into the matter, given how helpful it would be to have an early warning system.
The science itself is pretty murky and mixed on the topic, but some studies have shown changes in animal behavior prior to earthquakes. A 2020 study tracked farm animal movements in Marche, Italy, where earthquakes are commonplace.
During the study, which tracked the animals for several months, there were 18,000 earthquakes in the region and 12 with a strength of four or higher on the Richter scale, giving the researchers plenty of data and movement to look at. The team found unusual behavior patterns up to 20 hours before a quake.
“The closer the animals were to the epicentre of the impending shock, the earlier they changed their behaviour," Professor Martin Wikelski, who led the study, said. "This is exactly what you would expect when physical changes occur more frequently at the epicentre of the impending earthquake and become weaker with increasing distance."
Though it's not known by what mechanism animals could sense earthquakes, the team suggested it could be that animals sense air ionization caused by large rock pressure, or even smell gases released by quartz crystals prior to a quake.
Though they say much more data from around the world is needed to create an actual early warning system, the team did sort of use it as an advanced warning in 2019. Whenever the animals, monitored via a collar, had significantly increased activity for at least 45 minutes a warning was sent to the team. They only received one of these warnings during data collection.
“Three hours later, a small quake shook the region,” Wikelski said. “The epicentre was directly below the stables of the animals.”
So, animals sense earthquakes, right? Well, it might not be that simple. A comprehensive statistical analysis of 180 peer-reviewed accounts of strange animal behavior prior to earthquakes, looking at everything from toads to elephants.
It concluded that the evidence was pretty unsubstantial, noting that most reports were "made retrospectively, i.e. the strange animal behavior is only recognized after the earthquake" and that baseline behavior was rarely defined. Strange behavior was also very loosely defined, with one report describing a tiger in China as "depressed" before a 1969 earthquake.
It may turn out that animals can sense earthquakes before humans with our fancy human equipment, but much more study is needed on the topic before we can say so conclusively.