Mating Toads can ‘predict earthquakes’ and seismic activity
Posted by Xeno on April 2, 2010
Common toads appear to be able to sense an impending earthquake and will flee their colony days before the seismic activity strikes.
The evidence comes from a population of toads which left their breeding colony three days before an earthquake that struck L’Aquila in Italy in 2009.
How toads sensed the quake is unclear, but most breeding pairs and males fled.
They reacted despite the colony being 74km from the quake’s epicentre, say biologists in the Journal of Zoology.
It is hard to objectively and quantifiably study how animals respond to seismic activity, in part because earthquakes are rare and unpredictable.
Some studies have been done on how domestic animals respond, but measuring the response of wild animals is more difficult.
Even those that have been shown to react, such as fish, rodents and snakes tend to do so shortly before an earthquakes strikes, rather than days ahead of the event.
However, biologist Dr Rachel Grant of the Open University, in Milton Keynes, UK, was routinely studying the behaviour of various colonies of common toads on a daily basis in Italy around the time a massive earthquake struck.
Her studies included a 29-day period gathering data before, during and after the earthquake that hit Italy on 6 April 2009.
The quake, a 6.3-magnitude event, struck close to L’Aquila city, about 95km (60 miles) north-east of Rome.
Dr Grant was studying toads 74km away in San Ruffino Lake in central Italy, when she recorded the toads behaving oddly.
Five days before the earthquake, the number of male common toads in the breeding colony fell by 96%. …
That is highly unusual for male toads: once they have bred, they normally remain active in large numbers at breeding sites until spawning has finished.
Yet spawning had barely begun at the San Ruffino Lake site before the earthquake struck.
Also, no weather event could be linked to the toads’ disappearance.
Three days before the earthquake, the number of breeding pairs also suddenly dropped to zero.
While spawn was found at the site up to six days before the earthquake, and again six days after it, no spawn was laid during the so-called earthquake period – the time from the first main shock to the last aftershock. …