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Hank tells us about new research into the question of how animals navigate from place to place - while the problem is still unresolved, we do have some hypotheses, and they all involve something called "magnetoreception."

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Here's something I wish I had: Magnetoreception, the ability to detect and navigate by magnetic fields.

People have been pondering how animals navigate since time immemorial, and until the 1950s scientists assumed that birds, at least, navigated the same way as ancient mariners, by the sun and the moon and the stars and, you know, sextants and astrolabes. But then, everything changed when researchers in Germany were studying robins in a shuttered lab, and they realized that, come migration time, the birds all started trying to get out of the same side of the cage, specifically, the side of the cage that Spain was on, which is where they all wanted to go. Since then, experiments have suggested over and over again that a variety of organisms, trout, bees, bacteria, turtles, birds, maybe even cows can detect magnetic fields and navigate by them. We just can't figure out how the frick they're doing it, but research continues.

This very year, 2012, a team of researchers at Germany's Ludwig Maximilian University came up with a theory. It could be that some navigating animals have specialized cells that contain magnetite, the strongest naturally magnetic material on Earth. It's already been shown that trout's facial nerves respond to electric signals when exposed magnetic fields. So, the German teams scraped some cells out of a Rainbow Trout's nose and put them in a microscope surrounded by magnetic coils and a rotating magnetic field. What they found is that some cells may be 1 in 10,000 actually spun in unison with the rotating magnetic field. These cellular magnets are tiny, but they responded to the magnetic field with about 100 times more force than the researchers predicted. The researchers theorize that these compass cells contain microscopic crystals of magnetite, or maybe some other iron rich mineral, and that nearby nerve cells pick up their spinning and transmit that information to the fish's brain to give it directions.

Very clever, but another mechanism for detecting magnetic fields could be in the eyes. Birds and a host of other animals have retinas that are chalk full of protein called cryptochrome, and cryptochrome can produce molecules called radicals, which have unpaired electrons. Now I'll spare you the details here, but pairs of these radicals can interact in such a way that they're affected by magnetic fields. And, since these reactions are taking place in the eye, it's possible that cryptochrome can actually allow animals to see magnetic fields. And wait! Those animals could include us. Yes, we have cryptochrome in our retinas too. Scientists are investigating a particular kind, called CRY2, that's known to function in other animals as a light-sensitive magnetic sensor.

Now, it's still not clear why birds can fly thousands of miles without a map, while I can't find my out of the Arby's parking lot, but CRY2 might explain why some people just have a sense of which direction to go, even in a new environment. As with all things, time and science will tell. You might say that magnetoreception is a field of research that we're still feeling our way through.

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