Bryan Keller holds a bonnethead shark next to the North Edisto River in South Carolina. Mr. Keller and other scientists found that sharks use Earth’s magnetic field as a sort of GPS. (Bryan Keller via AP)

Bryan Keller holds a bonnethead shark next to the North Edisto River in South Carolina. Mr. Keller and other scientists found that sharks use Earth’s magnetic field as a sort of GPS. (Bryan Keller via AP)

Have you seen someone use a GPS in a car or on a phone? Sharks have their own way to find directions.

Have you seen someone use a GPS in a car or on a phone? Sharks have their own way to find directions.

A magnetic field is the area around a magnet that pulls and pushes other magnetic objects. The sewing pins that are stuck are inside the magnet’s magnetic field.

A magnetic field is the area around a magnet that pulls and pushes other magnetic objects. The sewing pins that are stuck are inside the magnet’s magnetic field.

These little pieces of metal illustrate the magnetic field of a bar magnet.

These little pieces of metal illustrate the magnetic field of a bar magnet.

Roslyn Boden watches two bonnethead sharks swim at the Greater Cleveland Aquarium in Cleveland, Ohio. (AP/Tony Dejak)

Roslyn Boden watches two bonnethead sharks swim at the Greater Cleveland Aquarium in Cleveland, Ohio. (AP/Tony Dejak)

Sharks Use Built-in GPS

Posted: July 1, 2021

Scientists made a remarkable discovery about sharks. Apparently, the marine animals use the Earth’s magnetic field as a natural Global Positioning System (GPS). Hang a left. Swerve right. Straight ahead! The magnetic field helps sharks navigate the world’s oceans.

A magnetic field is the area around a magnet that pulls and pushes other magnetic objects. Sharks certainly aren’t magnetic! So how does the Earth’s magnetic field guide them?

“We know that sharks can respond to magnetic fields,” says Bryan Keller. He is a shark researcher. “We didn’t know that they detected it to use as an aid in navigation. . . . Sharks can travel [12,427] miles and end up in the same spot.”

For years, scientists have wondered how sharks migrate such long distances. They travel in the open ocean where there are few landmarks like coral reefs to guide them. But they keep coming back to the same place. Over and over again. Why don’t they get lost?

Looking for answers, scientists from Florida State University studied bonnethead sharks. That’s a kind of hammerhead that lives on both American coasts. Bonnetheads return to the same coastal inlets every year.

The scientists exposed 20 sharks to magnetic conditions like they would experience in the ocean. Could they feel a pulse? Did the water move? Could they see the magnetic clues?  The scientists watched each shark carefully. They noticed that the sharks began to swim north when the magnetic cues made them think they were south of where they should be. It’s as if their bodies could tell they weren’t where they needed to be. Flip around. Swerve left. Onward!

More studies are necessary. How do sharks detect magnetic fields? How much does the field tell them about their location? Do all sharks find their way around the ocean in the same way? Probably. After all, great whites make cross-ocean journeys just like bonnetheads. It makes sense that God might use the same design for both.

Isn’t the usefulness of God’s design amazing? He created the magnetic field. And He gifted marine animals with a sensitivity to it to help them survive. That’s truly magnificent!