Tag: navigation

Those Magnetic Neurons Birds Use to Steer? They're Not Neurons, and Aren't For Steering.

By Veronique Greenwood | April 12, 2012 2:53 pm

pidgie

What’s the News: One of the leading theories explaining why birds can travel thousands of miles each year without getting lost is that they are equipped with an internal compass on their beaks: iron crystals in cells there could be orienting to the Earth’s magnetic field, sending a message to their brains that helps them steer.

It turns out, though, that those beak cells, which had been previously identified as neurons capable of sending such a message, aren’t neurons at all. A new study shows convincingly that those iron-bearing cells are macrophages, immune cells that could never play that role. Birds’ magnetic navigation skills must be coming from somewhere else.

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CATEGORIZED UNDER: Living World, Top Posts

News Roundup: Even 30 Miles Away, Sharks Can Home in on a Location

By Andrew Moseman | March 2, 2011 12:12 pm

  • Shark seek: Tiger sharks and thresher sharks remember and zero in on specific places to hunt for food in an area that might be 30 miles across. That shows they might possess not only the ability to navigate by smell or by the Earth’s magnetic field, but also broader spatial memory for their home range.
  • “If you eat by shoving your entire writhing body into your meals, your dinner companions are probably going to leave.” The hagfish, however, has no such concern for manners: It absorbs its nutrients right through its skin.
  • We be jammin’: Satellite provider Thuraya Telecommunications and news channel Al Jazeera both report that sources in Libya are illegally trying to jam their signals, and traced the attempts to “a Libyan intelligence service facility south of Tripoli.”
  • British researchers discover a way to use urine tests to screen for prostate cancer—and potentially double the accuracy of current methods.
  • Numismatist power: Coin experts create interactive digital maps of coins through history and where they came from, putting a treasure trove of information at historians’ fingertips.
  • Super honey from down under: A myrtle native to Australia produces honey packed with antibacterial compounds that can stymie even antibiotic-resistant microorganisms like MRSA.

Image: Wikimedia Commons

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
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