Many animals are believed to have a “sixth sense” about natural disasters, but research published today suggests common toads really can sense a coming earthquake.
Researchers at the Open University studying toads in Italy, found 96 per cent of males abandoned a breeding site 74km from the epicentre of the earthquake that hit L’Aquila in 2009, five days before it struck.
The number of pairs at the site dropped to zero three days before the quake, according to the study published in the Zoological Society of London's Journal of Zoology.
And there was no fresh toadspawn laid at the spot from the date the earthquake struck to the last significant aftershock of more than 4.5 on the Richter scale.
According to the researchers, male toads would normally remain in the breeding sites from the point mating activities get under way until spawning is complete. The scientists believe the toads could be able to detect environmental changes, such as the release of gases or charged particles from the ground, before seismic events.
The coming earthquake appears to have prompted them to break off from breeding and evacuate the site. Their exodus coincided with disruptions in the ionosphere, the uppermost electromagnetic layer of the Earth’s atmosphere, which could be the result of the release of radon gas and gravity waves prior to an earthquake.
Dr Rachel Grant, who was studying the impact of the lunar cycle on the toads when the earthquake struck, said: “Our study is the first to document animal behaviour before, during and after an earthquake," she said. “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 earthquake early warning system.”
Dr Grant said she was “very surprised” by the toads’ unexpected disappearance for five days before the earthquake struck, and it was only after the event that a colleague suggested the two events could be linked.
She believes the amphibians could have evolved to evacuate an area when they sensed the changes associated with a quake.
Earthquakes can cause flooding, rock-falls or landslides which could devastate a population gathered in a single spot to breed, and the toads may have headed to higher, safer ground.
“An earthquake could wipe out a population in that area. This particular species are very dispersed and can live up to a mile or two from their breeding site.
“A landslide or flood could wipe out virtually 100 per cent of the males, and quite a lot of the females,” she said. “A day after the earthquake, they all started coming back. The numbers were still lower than normal and remained low until after the last aftershock.”
While earthquakes are a rare phenomenon, toads have been around on the planet for 450 million years - long enough to evolve a response to such potentially catastrophic events, she suggested.
And as for a sixth sense, she said animals were able to detect things that humans could not - but with their ordinary senses, which could be much more sensitive to certain things than ours.
Reuters