LONDON — When it comes to predicting earthquakes, toads — warts and all — may be an asset.

British researchers said yesterday 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.

Since ancient times, anecdotes and folklore have linked unusual animal behavior to cataclysmic events such as earthquakes, but hard evidence has been scarce.

A new study by researchers from the Open University is one of the first to document animal behavior before, during, and after an earthquake.

The scientists were studying the common toad — bufo bufo — at a breeding colony 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.’’

“A day after the earthquake, they all started coming back,’’ said Grant, the report’s lead author.

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