Can toads (and other animals) predict earthquakes?
The devastating December 2004 Indian Ocean tsunami, generated by a 9.0 magnitude earthquake, was one of the worst disasters in recorded history, with a death toll of more than 283,000.
Some of the strangest stories that came out after the tsunami were about the unusual behavior of animals before and during the tsunami. Many animals moved to higher ground well before the tsunami and at least a few people followed them. As reported in National Geographic News, the ancient Jarawa tribe of the Andaman Islands, finely attuned to their environment and to the movement of the animals, suffered almost no casualties when the tsunami hit their islands.
Recently, as reported in AOL news, behavioral biologists Rachel Grant and Tim Halliday of the Open University (Great Britain) noticed that large numbers of toads fled a breeding area five days before a magnitude-6.8 earthquake struck L’Aquila, Italy, in April 2009.
Grant had been studying the breeding habits of toads at San Ruffino Lake, which is 46 miles from the epicenter. Normally, as the full moon approached, more and more toads would come down to a shallow pool at the lake’s edge from the surrounding hills to breed. (We wrote a post, Frog Moon Dance, about her research last summer.) Grant monitored their numbers, recording the weather and other environmental conditions.
Last year, she and an assistant were tracking the toads leading up to the full moon when they noticed a surprising change. Five days before the earthquake, 96 percent of the male toads were gone. In the past, Grant had noticed that a change in the weather could keep toads away for a day or so. “But usually the day after, they come back. I’d never seen it happen where there were none for several consecutive days,” she said. Grant checked the climate records, but could find no weather-related reasons for the changes in the toads’ behavior.
In this month’s Journal of Zoology, Grant and Halliday speculate that the toads may have picked up naturally occurring magnetic fields prior to the earthquake that encouraged them to flee. Grant hopes that she’ll be able to explore the phenomenon again in the coming years by enlisting volunteers in earthquake-prone areas such as Indonesia to see if the behavior occurs again.
I find it interesting that people living in small villages around Mt. Vesuvius in Italy no longer wait for the official warnings from seismologists and scientists. They carefully observe the behavior of the stray dogs. If the strays are quiet, they are assured that the volcano is not in imminent danger of erupting.*
As we learned in the 2004 tsunami, even a few minutes warning would have saved hundreds, if not thousands, of lives. Seismologists are not always able to predict in advance the exact day of earthquakes or volcanic eruptions. Some come on suddenly, as happened with the recent earthquakes in Haiti and China. It may be in our best interests to pay closer attention to what toads and other animals may be telling us.
*From UN Special No. 637, February 2005