Study: Many toads traveling might signal an impending earthquake

If you see more toads than usual hopping down the roads of your neighborhood, it could be an earthquake early warning signal, according to researchers at The Open University in the UK.

A study published in the Zoological Society of London's Journal of Zoology suggests that common toads (Bufo bufo) can detect the geodynamic precursors of an earthquake days ahead and shift from breeding to evacuating. Researchers from The Open University report that five days before an earthquake struck L'Aquila, Italy on April 6, 2009, 96 percent of a male toad population abandoned their breeding site, located just 74 km from the temblor's epicentre. No paired toads remained at the site three days ahead of the 6.3 magnitude quake and no fresh spawn was found there from the date of the quake until after the date of the last aftershock greater than 4.5 in magnitude. Typical behavior for the male-dominated breeding sites is for toads to stay through the entire spawning season. According to the researchers, who observed the site for nearly a month, certain seismic precursors coincided with the toads' behavior changes: Disruptions in the uppermost electromagnetic layer of the earth's atmosphere (ionosphere) and the release of radon gas or gravity waves. Lunar phases and changing weather conditions were taken into account as environmental factors already known to alter toad behavior. Lead author Dr. Rachel Grant writes, "Our findings suggest 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." This new study is one of the first to document animal behavior before, during and after an earthquake, notes Grant. The China Seismological Bureau has used changes in animal behavior to predict 20 earthquakes over two decades, a small percentage of the earthquakes that struck during that period, according to an earlier article on Digital Journal.