导读：雷切尔 格兰特博士领导进行了这项研究。他说：“这是是首个记录震前、震中和震后动物行为的研究。我们的研究结果表明，蟾蜍能够探知震前征兆，比如气体的释放和探测带电粒子。这些构成了蟾蜍预知地震的预警系统。”
Toads can 'predict earthquakes' and seismic activity
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.
"Our study is one of the first to document animal behaviour before, during and after an earthquake," says Dr Grant.
She believes the toads fled to higher ground, possibly where they would be at less risk from rock falls, landslides and flooding.
Sensing danger
Exactly how the toads sense impending seismic activity is unclear.
The shift in the toads' behaviour coincided with disruptions in the ionosphere, the uppermost electromagnetic layer of the earth's atmosphere, which researchers detected around the time of the L'Aquila quake using a technique known as very low frequency (VLF) radio sounding.
中文相关背景：
据国外媒体报道，科学家研究发现，蟾蜍能够提前5天探知地震的发生。
2009年4月意大利拉奎拉地区遭遇地震，造成重大伤亡和财产损失。英国开放大学(Open University)的科研人员研究发现，在地震发生前，拉奎拉城外的蟾蜍大举逃离栖息地。科研人员注意到，尽管当时恰逢蟾蜍重要的繁殖季节，但96%的雄性蟾蜍在地震5天前逃离了它们的栖息地。而地震3天前，配对的蟾蜍数量下降为零。而且，地震发生后直到最后一次余震发生期间，当地并没有发现蟾蜍所产下的卵。
在蟾蜍繁殖地，雄性蟾蜍占据统治地位，而且当交配行为开始后，蟾蜍会待在原地一动不动，直到产下卵为止。
雷切尔?格兰特博士领导进行了这项研究。他说：“这是是首个记录震前、震中和震后动物行为的研究。我们的研究结果表明，蟾蜍能够探知震前征兆，比如气体的释放和探测带电粒子。这些构成了蟾蜍预知地震的预警系统。”
据信，地震前夕地球内部会释放出氡气和重力波，并被大气层反射回来，会被蟾蜍探知。
