
How some animals use the Earth’s magnetic field to navigate - NicoJuicy
https://www.economist.com/the-economist-explains/2018/09/25/how-some-animals-use-the-earths-magnetic-field-to-navigate
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everdev
If the magnetic field flipped 780k years ago [0] and animals do rely on it for
survival (like migrations), wouldn't we see mass extinctions around those
magnetic flips? Or maybe magnetic field navigation is a weak signal out of
many?

[0] [https://www.livescience.com/18426-earth-magnetic-poles-
flip....](https://www.livescience.com/18426-earth-magnetic-poles-flip.html)

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TeMPOraL
If animals learn where to migrate from their parents/flock, then it would be
reasonable to assume they learn the relation between where they should be
going and what their magnetosense is telling them. The article implies that
even during transition, the magnetic field is pretty much constant within a
lifetime of any individual animal.

Now a tangential question I have is: how the hell do animals know where they
should migrate? Is this learned from observation, or do they have some innate
idea of where they should go?

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notduncansmith
I recently learned that salmon find their way back to their birth stream
partly by smell: [https://www.scientificamerican.com/article/how-do-
spawning-f...](https://www.scientificamerican.com/article/how-do-spawning-
fish-navigate-back/)

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partycoder
Cows face north-south when grazing.

~~~
jacquesm
That was one of the most interesting applications of Google maps that I know
of.

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pwaivers
So this is pretty incredible. We know that animals can detect magnetic fields,
but we don't know how they sense it!

I hope one day humans can have the same sense.

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AstralStorm
We actually kind of have a few putative mechanisms.

Certain proteins in eyes of some birds are magnetosensitive.

[https://www.sciencealert.com/birds-see-magnetic-fields-
crypt...](https://www.sciencealert.com/birds-see-magnetic-fields-cryptochrome-
cry4-photoreceptor-2018)

Pigeons apparently may have magnetosensitive balance sense for some reason.

[https://www.nature.com/news/pigeons-may-hear-magnetic-
fields...](https://www.nature.com/news/pigeons-may-hear-magnetic-
fields-1.10540)

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tartuffe78
Answer: We don't know yet.

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glandium
Do we really not know, though? "Birds can see Earth's magnetic fields because
of cryptochromes in their eyes"
[https://news.ycombinator.com/item?id=16823201](https://news.ycombinator.com/item?id=16823201)

~~~
AstralStorm
It's a putative mechanism not a fully explored one.

