Animals may sense chemical changes in groundwater that occur when an earthquake is about to strike.
This, scientists say, could be the cause of bizarre earthquake-associated animal behaviour.
Researchers began to investigate these chemical effects after seeing a colony of toads abandon its pond in L'Aquila, Italy, in 2009 - days before a quake.
They suggest that animal behaviour could be incorporated into earthquake forecasting.
The team's findings are published in the International Journal of Environmental Research and Public Health. In this paper, they describe a mechanism whereby stressed rocks in the Earth's crust release charged particles that react with the groundwater.
Animals that live in or near groundwater are highly sensitive to any changes in its chemistry, so they might sense this days before the rocks finally "slip" and cause a quake.
The team, led by Friedemann Freund from Nasa and Rachel Grant from the UK's Open University hope their hypothesis will inspire biologists and geologists to work together, to find out exactly how animals might help us recognise some of the elusive signs of an imminent earthquake.