Toads' Seismic Sensitivity

Who needs high tech seismic monitoring devices? Why not just enlist a few toads?

A study published online today in the Journal of Zoology reports that common toads may be able to detect impending seismic activity and alter their behavior from breeding to evacuation mode.

Researchers from The Open University studying toads about 46 miles from the epicenter of the 2009 L’Aquila earthquake in Italy found that 96% percent of the males abandoned their breeding grounds five days before the earthquake hit. As soon as the earthquake was over, they returned. This behavior was viewed as unusual because breeding sites are male-dominated and the toads would normally remain from the point that breeding activity begins, to the completion of spawning.

This shift in the toads’ behavior coincided with disruptions in the uppermost layer of the Earth’s atmosphere, called the ionosphere, which was detected using very low frequency radio sounding.

In this case the cause of the ionosphere disruptions was not confirmed, but the release of radon gas or gravity waves prior to an earthquake have both been attributed to changes in atmospheric electric fields and currents.

While there have been many suspicions of animals sensing earthquakes, it’s been difficult to demonstrate. In this case, however, the researcher happened to be in the right place at the right time. Biologist and lead author of the study, Rachel Grant, was studying toads in that area for four years when the earthquake hit. Now she’s published ground-breaking research.

“Our study is one of the first to document animal behavior before, during, and after an earthquake. 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 an earthquake early warning system.”

Creative Commons image by WWalas