Most of us have heard theories about how cows lying down means rain is on the way (it’s a logical reaction, but how would they know?), but now researchers believe animals may be able to detect impending earthquakes.

The study began after an entire colony of 96 toads abandoned a pond in Italy in 2009, preceding an earthquake in the area by several days. That lead a team lead by staff from NASA and the British Open University to explore the idea that the toads had some sort of insight.

Their theory (PDF) is that when tectonic plates begin to undergo stress in the run-up to a quake, they activate oxygen-based electrons known as “positive holes”. These are able to make their way out of the affected rocks, through secure rocks and to the surface. This causes air ionization, as well as turning water to hydrogen peroxide, which is potentially toxic.

While humans might struggle to notice the effect, it seems likely that animals which inhabit this groundwater are naturally much more sensitive to chemical imbalances, and thus would leave the area when the change starts occuring.

The researchers have been testing the chemical effects of putting rock under stress and believe their theory is credible but needs more rigorous and wide-ranging testing. They’ve also noted the air ionization may increase seratonin levels in animals, another cue to leave the scene.

There have been several anecdotal accounts of similar evacuations before quakes, but this is the first time a rational explanation has been tested in this way. The researchers say the animal movements certainly aren’t a guaranteed way of predicting a quake, but that it could be included as one of a range of signals.

[Picture Source: delgrosso – Flickr (CC)]