Impending quakes detected by toads

April 01, 2010 12:18 am | Updated November 12, 2016 05:40 am IST

Common toads ( Bufo bufo ) can detect impending seismic activity and alter their behaviour from breeding to evacuation mode, suggests a new study in the Zoological Society of London's (ZSL) Journal of Zoology .

Researchers from The Open University reported that 96 per cent of male toads in a population abandoned their breeding site five days before the earthquake that struck L'Aquila in Italy in 2009. The breeding site was located 74 km from the earthquake's epicentre.

The number of paired toads at the breeding site also dropped to zero three days before the earthquake. No fresh spawn was found at the site from the date that the earthquake struck to the date of the last significant aftershock (magnitude >4.5).

Breeding sites are male-dominated and the toads would normally remain in situ from the point that breeding activity begins, to the completion of spawning.

This shift in the toads' behaviour coincided with disruptions in the ionosphere, the uppermost electromagnetic layer of the earth's atmosphere, which were detected using very low frequency (VLF) radio sounding.

The release of radon gas, or gravity waves prior to an earthquake have both been attributed to changes in atmospheric electric fields and currents. Other environmental changes that affect toad behaviour, including lunar phases and changing weather conditions were accounted for.

The number of toads breeding at the study site was known to increase during a full moon.

However, following the earthquake the number of toads present during a full moon was 34, in comparison to between 67 and 175 individuals in previous years.

“Our study is one of the first to document animal behaviour before, during and after an earthquake.

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,” says lead author Dr Rachel Grant.

0 / 0
Sign in to unlock member-only benefits!
  • Access 10 free stories every month
  • Save stories to read later
  • Access to comment on every story
  • Sign-up/manage your newsletter subscriptions with a single click
  • Get notified by email for early access to discounts & offers on our products
Sign in

Comments

Comments have to be in English, and in full sentences. They cannot be abusive or personal. Please abide by our community guidelines for posting your comments.

We have migrated to a new commenting platform. If you are already a registered user of The Hindu and logged in, you may continue to engage with our articles. If you do not have an account please register and login to post comments. Users can access their older comments by logging into their accounts on Vuukle.