TOADS FORETELL A COMING EARTHQUAKE?

LONDON - British researchers said Wednesday that they observed a mass exodus of toads from a breeding site in Italy five days before a major tremor struck, suggesting the amphibians may be able to sense environmental changes, imperceptible to humans, that foretell a coming quake.

• Researchers from the Open University were studying toads in central Italy when they noticed a sharp decline in the number of animals at the site. Days later, a 6.3-magnitude earthquake hit, killing hundreds of people and badly damaging the town of L'Aquila.
• Researcher Rachel Grant said the findings suggested "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."
• Initially puzzled by the toads' disappearance in the middle of the breeding season, the scientists tracked the population in the days that followed. They found that 96 percent of males — who vastly outnumber females at breeding spots — abandoned the site, 46 miles (74 kilometers) from the quake's epicenter, five days before it struck on April 6, 2009.
• The number of toads at the site fell to zero three days before the quake, according to the study, published in the Zoological Society of London's Journal of Zoology.
• "A day after the earthquake, they all started coming back," said Grant, the report's lead author. "The numbers were still lower than normal and remained low until after the last aftershock."
• She said one possibility is that the animals sensed a change in the amount of radon gas emitted by the Earth because of the buildup of pressure prior to a quake.
• Scientists also have surmised that animals may be able to detect minor tremors imperceptible to humans, or that they sense electrical signals emitted by rocks under stress before an earthquake.
• Grant said the sense may be the result of millions of years of evolution, a trigger that tells the toads to move to safer ground.

Source: AP, Yahoo News