How Turtles Use Earth's Magnetic Field To Navigate Ocean Voyages

By Andrew Moseman | February 25, 2011 10:00 am


From Ed Yong:

In 1996, a loggerhead turtle called Adelita swam across 9,000 miles from Mexico to Japan, crossing the entire Pacific on her way. Wallace J. Nichols tracked this epic journey with a satellite tag. But Adelita herself had no such technology at her disposal. How did she steer a route across two oceans to find her destination?

Nathan Putman has the answer. By testing hatchling turtles in a special tank, he has found that they can use the Earth’s magnetic field as their own Global Positioning System (GPS). By sensing the field, they can work out both their latitude and longitude and head in the right direction.

By testing turtle hatchlings in a tank surrounded by magnets he could control, Putman showed turtles could sense it if he reversed the magnetic field around them and would begin heading in the opposite direction.

For more about the experiment—and how turtles can travel so far at such high stakes with just magnetism to guide them—check out the rest of Ed’s post at Not Exactly Rocket Science.

Related Content:
Not Exactly Rocket Science: Foxes use the Earth’s magnetic field as a targeting system
Not Exactly Rocket Science: Robins can literally see magnetic fields, but only if their vision is sharp
80beats: Did Earth’s Magnetic Field Have a Fast Flip-Flop?

Image: Wikimedia Commons

CATEGORIZED UNDER: Environment, Living World
  • Stevo

    Fascinating! Forgive my ignorance, but I’m wondering when this feature developed in the turtles. Would it have been since the last geomagnetic reversal? Or did they have a way to cope with such a reversal?

    I can just image a family of turtles 780,000 years ago:

    “All right kids, we’re going on vacation to Japan!”
    “Yayyyy!”
    Months later …
    “Honey, I don’t think this is Japa-’”
    “I know this isn’t Japan! Just give me a minute to figure it out!”
    “Why don’t we just ask that dolphin over there?”
    “WE’RE NOT ASKING FOR DIRECTIONS, DANG IT!!”

    Wow. I need sleep.

  • Matt

    Oh my, what a fascinating discovery! I wonder over the bioloical mechanisms by which they accomplish this feat and Stevo nice imaginative dialogue it gave me a laugh

  • m

    LOL at Stevo.

    a great question though!

    Actually…i “think” that the did acclimatize to pole reversals. There was a study done with birds that do the same thing. Even though the magnetic field was reveresed, the birds tracked the sun.

    turtles might do the same thing.

    i bareley remember the article though, and probably destroyed the summary….but you should be able to google it.

  • Matt B.

    I assume they use the direction of the field to align north to south, and the angle of the field to the ground to figure out their latitude. Someone should make an electronic device that does that.

    I also assume the turtles learn to calibrate their magnetic navigation using smaller-scale visual perception rather than navigating instinctively on magnetics alone (similar to how astronomers calibrate longer-range methods of determing distance using the overlap with smaller-scale methods).

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