New research suggest dolphins might use the Earth’s magnetic field as a kind of GPS device. A recent study by researchers in France uncovered evidence dolphins use magnetoreception. It’s likely the dolphins use this extra sense as a way to navigate the ocean.

During the study, researchers used two barrels–one with magnetized blocks inside and one with demagnetized blocks inside–and monitored which barrel six bottlenose dolphins responded to. All six dolphins swam quickly toward the barrel with magnetized blocks indicating the presence of magnetoreception.

Dolphins aren’t the only animal with this sense. Decades of research have shown other animals including salmon, fruit flies, honeybees, sea turtles, and migratory birds all possess magnetoreception.