Gray whales migrate more than 10,000 miles up and down the western coast of North America, longer than almost any other mammal. In summer, they head north, often as far as Alaska’s Aleutian Islands, and in the winter, they travel south, giving birth off the coast of Mexico.

New research suggests that solar storms may temporarily interfere with their ability to navigate on these long treks, perhaps even leading them to become stranded. It points to the possibility that gray whales may use Earth’s magnetic fields to navigate. Currently they are only conclusively known to find their way using their vision.

Solar storms—events on the sun in which large quantities of high-energy particles are ejected—bombard Earth with unusually high levels of