A rescue dog working after the 2017 Puebla earthquake in Mexico. (Reuters pic)On Dec 26, 2004, an earthquake struck off the west coast of northern Sumatra in Indonesia and triggered a deadly tsunami that killed hundreds of thousands around the region.
Many heartbreaking stories emerged from the tragedy, but there is one that remains of particular interest to scientists.
According to many eyewitnesses, many animals behaved oddly just before the tsunami struck, with many fleeing to higher ground.
This is not the first time humans have noticed this phenomenon, and it is likely it will not be the last.
In 2012, researchers noted that goats grazing on the slopes of Italy’s Mount Etna fled hours before the volcano erupted.
Just before an earthquake struck the Indian state of Gujarat in 2001, dogs were reported to be barking incessantly and running around in a panic.
On Feb 4, 1975, the authorities of the Chinese city of Haicheng ordered an evacuation after receiving reports of strange animal activity, saving lives when an earthquake struck shortly after.
A rescue dog searches for survivors in the rubble of a house which collapsed after the 2016 Kumamoto earthquakes in Japan. (AFP pic)Ancient Greek historians wrote of rats, weasels and snakes fleeing the city of Helike before an earthquake levelled the area in 373BC.
With all of these recorded instances, is it safe to say that animals are capable of predicting earthquakes? The answer is more complicated than one might think.
It is known that animals have survival instincts that allow them to hunt or evade predators, and perhaps it is these instincts that help them predict imminent disasters.
For example, when a storm is about to hit, birds hunker down as they can detect the change in air pressure. Even fish have been known to flee to deeper water when a typhoon is imminent.
But how do animals predict earthquakes?
Some scientists suggest that animals sense the rumbling in the earth’s crust, while others suggest they detect the gases released from the ground.
Soldiers with specially-trained dogs search for survivors amid the ruins of buildings knocked down in the 2017 Puebla earthquake. (AFP pic)Earthquakes can create infrasonic sounds, of a frequency lower than the human ear can detect, which could be how animals pick them up.
Many scientists remain sceptical that animals are a good indicator of natural disasters, and it is hard to prove that they are. Animals simply behave strangely from time to time, and it is not a mathematical impossibility that their misbehaviour coincides with a natural disaster.
If an animal behaves strangely and there is no natural disaster shortly after, people would not have taken much notice of the behaviour.
It is widely agreed, however, that animal senses allow them to detect environmental changes long before humans can.
It is also likely that animals behave strangely before a natural disaster because they are spooked by whatever environmental change they are detecting.
Ultimately, animals are unlikely to have a “sixth sense” of any sort, but are simply more observant of signs of imminent natural disasters than humans.