A new study suggests toads can detect impending earthquakes, calling to mind other examples of animals sensing disasters before they hit.
Toads as an Earthquake Prediction System
In April 2009, British researchers were studying the common toad at a breeding site in central Italy when they “observed a mass exodus of toads,” Jill Lawless reports for the Associated Press.
Just five days later, a 6.3-magnitude earthquake hit, killing some 150 people and causing extensive damage to the town of L’Aquila.
Rachel Grant, a researcher at Open University and lead author of one of the first studies to document animal behavior surrounding earthquakes, believes “that toads are able to detect pre-seismic cues such as the release of gases and charged particles, and use these as a form of earthquake early warning system.”
According to the study, “Predicting the unpredictable; evidence of pre-seismic anticipatory behaviour in the common toad,” the toad population at the breeding site dropped to zero three days prior to the quake.
“A day after the earthquake, they all started coming back,” Grant told the AP. “The numbers were still lower than normal and remained low until after the last aftershock.”
Animals Sensing Earthquakes
“The belief that animals can predict earthquakes has been around for centuries,” Maryann Mott wrote for National Geographic News in 2003. In 373 B.C., historians wrote that rats, weasels and snakes made a mass exodus from the Greek city of Helice days before an earthquake destroyed the city. Other examples exist from throughout the centuries. Reports include bees leaving their hive, catfish moving violently and chickens refusing to lay eggs. Pet owners also have examples of their cats and dogs behaving strangely before a quake.
To date, seismologists can’t predict when or where the next earthquake will hit, and scientists don’t know what, if anything, animals sense before a quake. Some, like Grant, think they can detect changes in the Earth’s gases. Others wonder if animals’ more sensitive hearing and other senses allow them to feel vibrations that humans can’t, or detect electrical changes.
Although some researchers continue to pursue the idea that animals can be used as an early warning prediction system, others remain skeptical. “What we’re faced with is a lot of anecdotes,” Andy Michael, a geophysicist at United States Geological Survey, told Mott. “Animals react to so many things—being hungry, defending their territories, mating, predators—so it’s hard to have a controlled study to get that advanced warning signal.”
The PBS show “Nature” examined the issue in 2005 in “Can Animals Predict Disaster?” Watch the full episode online to see “ancient ideas about how animals can predict disaster which are now gaining credence in scientific circles.”
Animals Spared in 2004 Indian Ocean Tsunami
Sources in this Story
- US News and World Report (AP): Study suggests toads can detect coming earthquakes
- The New York Times: Italians Comb Through Rubble After Quake
- Wiley InterScience: Journal of Zoology: Predicting the unpredictable; evidence of pre-seismic anticipatory behaviour in the common toad
- National Geographic News: Did Animals Sense Tsunami Was Coming?
- National Geographic News: Can Animals Sense Earthquakes?
- PBS: Nature: Can Animals Predict Disaster?
- CBS News: 60 Minutes: Sea Gypsies Saw Signs In The Waves
- findingDulcinea: NASA Scientists Explore Earthquake Prediction System
- findingDulcinea: New Tools Could Lead to Earlier Earthquake Warnings
Perhaps the most recent and most startling example of animals fleeing before an impending disaster was the 2004 tsunami that devastated the coastlines of India and Sri Lanka.
According to eyewitnesses, elephants screamed and headed for higher ground, flamingoes left their low-lying breeding areas, and zoo animals and dogs refused to go outside, Maryann Mott reported for National Geographic in 2005. Although the tsunami, triggered by a magnitude-9 quake, killed more than 150,000 people, “[r]elatively few animals have been reported dead,” Mott wrote.
Indigenous Tribes Also Escaped Tsunami
Animals weren’t the only ones who sensed impending disaster. As Bob Simon reported for “60 Minutes” in 2005, “[T]here’s one group who live precisely where the tsunami hit hardest who suffered no casualties at all.” The Moken people, who live a nomadic lifestyle on the Andaman Sea, saw the signs in the sea.
“The water receded very fast and one wave, one small wave, came so they recognized that this is not ordinary,” Dr. Narumon Hinshiranan, an anthropologist who speaks the Moken language, told Simon.
The water wasn’t the only clue. The Moken also noticed that animals were acting strangely: Elephants headed for higher ground and dolphins swam for deeper waters. And the cicadas, “which are usually so loud, suddenly went silent.”
The Moken climbed to higher ground and were saved, while their villages were completely destroyed.
While animals rely on their keen senses, and indigenous tribes like the Moken rely on their intimate knowledge of their immediate environment, scientists continue to struggle to find a reliable earthquake prediction system.
NASA and U.K.-based scientists are working together to investigate the possibility of a satellite-based earthquake warning system that could detect electrical changes in the Earth’s atmosphere.
Other seismologists believe that ultrasensitive new instruments that measure changes in rock could allow them to detect earthquakes hours in advance.
The consequences of earthquakes can be disastrous, especially for impoverished countries. Take a look at the science behind the earthquake and its various effects in history.