Ed Yong writes:

The first clear evidence that some animals have a magnetic sense came from a simple-enough experiment—put an animal in a box, change the magnetic fields around it, and see where it heads.

German scientists first tried this in the 1960s, with captive robins. When it came time to migrate, the birds would hop in a particular direction, as if they innately knew the way to fly. But when the team altered the magnetic fields around the robins’ cages, the birds hopped along a different bearing. In later decades, researchers showed that other songbirds, sea turtles, spiny lobsters, bogong moths, and many other species can also be magnetoreceptive, using variations on this same experiment.

“But you can’t really do that with a whale,” says Jesse Granger, a biophysicist at Duke University.

Granger has good reason to think that whales should have a magnetic sense. “They have some of the most insane migrations of any animals on the planet,” she says. “Some of them almost go from the equator to the poles, and with astounding precision, traveling to the exact same area year after year.” But how? Smells will diffuse too broadly over such long distances. Visual landmarks like the sun or stars are useful, but whales also migrate on cloudy days. [Continue reading…]