Sea turtles, like the loggerhead (Caretta caretta) species, have an amazing way of finding their way across the ocean. They can swim thousands of miles and come back to the same beach where they were born to lay eggs. Scientists have learned that loggerhead turtles use Earth’s magnetic field to guide them. They have two parts to their navigation. One part is a “magnetic map” that tells them where they are. The other is a “magnetic compass” that tells them which way to go. The magnetic map lets turtles sense changes in the Earth’s magnetic field. These changes help them find certain places like feeding or nesting spots. This skill helps them return to the same beach every time they nest.

 

In 2025 a group of scientists found that turtles can learn and remember magnetic fields from different places. In a study young turtles in tanks learned to connect a certain magnetic field with food. They remembered this for months, which proved they could recall magnetic patterns over long periods. When they sensed the same field later they did an excited “turtle dance” by moving fast and circling in the water. This showed they remembered what the field meant. The compass part of their system works differently. It helps them keep the same direction while swimming. Tests showed that radio signals are capable of stopping the compass from working but do not affect their internal map. This shows the two systems are separate. Some scientists think the compass depends on light and quantum effects in their eyes while the map might depend on tiny crystals called magnetite in their heads. Others think bacteria that respond to magnetic fields might help turtles sense direction. Nobody knows for sure how the system works, but it is one of the biggest mysteries in animal science.

 

Humans have now made a new similar tool called MagNav. This new technology also uses Earth’s magnetic field for navigation. It helps people or machines find their way without GPS. MagNav measures local magnetic fields and tries to match them to detailed magnetic maps of the Earth. Each place on Earth has a unique magnetic pattern due to certain minerals underground like maghemite and pyrrhotite. New quantum sensors now make this system much more accurate. These sensors are very sensitive and can pick up tiny changes in magnetic fields. Tests showed MagNav can find its location within about 22 meters, which is far better than older navigation tools.

 

MagNav works even when GPS signals are lost or jammed. It is used by the military, pilots, and drones to keep track of their position in hard conditions. It can also be used in airplanes, ships, and self-driving cars. Some scientists are testing it for underwater vehicles and space robots where GPS does not work. MagNav can be used together with GPS and other tools so that if one fails, the others keep it working.

 

Sea turtles and MagNav both use Earth’s magnetic field to guide them. Turtles sense the field naturally while MagNav uses machines to do the same thing. Turtles learn from experience and do not need power or computers. MagNav needs electricity and pre-made maps. Turtles also use other clues like light, smell, and waves, while MagNav depends only on sensors and software. Turtles are more energy efficient since their brains do all the work. Scientists hope to make MagNav systems that can learn and adjust to new data just like turtles do.

 

By studying how turtles navigate people can now build better and more efficient navigation tools. The turtle’s two-part system shows how humans can be inspired by nature. Learning how their magnetic sense works might help scientists make new kinds of technology for medicine, space, and Earth studies. The way turtles find their way across the ocean could help humans make smarter and stronger navigation technology.