
How Do Animals Keep from Getting Lost? - jonbaer
http://www.newyorker.com/tech/elements/how-do-animals-keep-from-getting-lost
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Someone
1) Using a combination of mechanisms.

Dead reckoning using only a compass does you little good if you integrate over
days (or more: for migrating animals, integration period would be months),
more so if you are moving through water or air that itself moves in varying
directions at varying speeds that you cannot measure reliably (example: human
sailors sailing from the north coast of Spain into the English Channel
sometimes managed to end up west of Land's End
([https://en.m.wikipedia.org/wiki/Scilly_naval_disaster_of_170...](https://en.m.wikipedia.org/wiki/Scilly_naval_disaster_of_1707\)))

Homing pigeons, for example, are better at finding their home if they have had
time to fly around in its wider neighborhood. That way, if their imperfect
navigation methods bring them somewhere 30 miles from home, they recognize the
location and get home from there.

For homing pigeons, smell also has been mentioned as something they use to get
home.

It also wouldn't surprise me if homing pigeons living near the center of Paris
became better at getting home after the Eiffel Tower was built.

2) using the law of large numbers. Not all animals need to return for
migration to be a success for the species.

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aaron695
1) The article claims, the conference thinks you're wrong.

"This marked a change from previous years, Richard Nissen, a member of the
Institute, told me, when a range of other navigation aids were part of the
discussion: landmarks, olfactory cues, memory, genetics, polarized light,
celestial objects. “Everyone now seems completely sold on the idea that animal
navigation is based on magnetism,” Nissen said. Human-centric as it sounds,
most of the conference’s attendees believe that animals possess a kind of
compass."

When humans get lost it's only memory and random walking, it's a good theory
animals only have one more enhancement, small memory cues, magnetic and
randomness.

~~~
dhimes
My father had a pretty good innate sense of direction. He just said it was a
feeling, and he could cross-check with the sun, etc., if available- but could
do pretty well without it. He said he was pretty old when he realized that not
everybody could do that. Perhaps it's not totally gone from humans.

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Erik816
It's hard to get lost if you don't have anywhere you need to be.

~~~
jcoffland
Thousands of HN readers prove this statement wrong every day.

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trvlngwlbry
Side note: Two weeks ago, a friend told me that dogs turn their bodies to poop
in a north-south axis. I couldn't believe it and couldn't believe that I
hadn't noticed before. So this was a timely read.

The article begged the question for me: Does the biocompass come into play for
humans? Does anyone know of any examples of cultural/tribal traditions/oral
histories that suggest that humans can improve their wellbeing by being aware
of Earth's magnetic fields for various tasks?

~~~
brc
I read that article and starting watching my dog, who tends to do his business
while walking. It's not true for my dog at least. There really is no rhyme or
reason though he will tend to go parallel to a path if there is one.

So I'm not convinced on the north/south axis thing, and not just because of my
anecdata, but because it sounds like one of those internet facts like duck
quacks don't echo.

~~~
HeyLaughingBoy
It's a bit off topic, but having raised ducks, I think I know the reason for
that "fact."

Duck quacks have an odd sound sometimes, almost like an echo in itself. I've
only noticed it when they're on the ground; in the air they seem to quack
differently. Anyway, with a quack that already sounds a bit like an echo, I
could see a case where the quack was actually echoing against a hard surface,
but not sounding any different from the "normal" quack.

My ducks flew away years ago, so I can't do any scientific testing now...

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jonah
My uncle works with desert tortoises in the Mojave. On some projects they find
all the animals in a certain area, attach radio transmitters, and translocate
them to another valley.

How they respond varies. Some make take up residence in the new area while
others make a bee line towards home.

~~~
TheOtherHobbes
Not sure if science or performance art.

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wvenable
Has anyone tried slapping a magnet on these migratory animals and testing
whether or not they get hopelessly lost?

~~~
GuiA
From the article:

 _In the early nineteen-sixties, a German graduate student named Wolfgang
Wiltschko began conducting experiments with European robins, which he thought
might find their way by picking up radio waves that emanated from the stars.
Instead, Wiltschko discovered that if he put the robins in cages equipped with
a Helmholtz coil—a device for creating a uniform magnetic field—the birds
would change their orientation when he switched the direction of north._

~~~
shmageggy
It's been done more recently than that too. Here's one experiment with sea
turtles:
[http://jeb.biologists.org/content/199/1/73](http://jeb.biologists.org/content/199/1/73)

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jonah
A few miles from where I live is a eucalyptus grove where monarchs overwinter.
There are other similar eucalyptus groves nearby without butterflies. Not only
do they make it to Mexico, they stop over at this exact grove year-after-year.

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mh-cx
As an absolute novice in genetics I wonder if you couldn't use CRISPR to
supress the expression of this MagR protein and see if the animals can still
find their way. If not, why not?

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Maultasche
I wonder what happens when the Earth's magnetic poles reverse, like they have
in the past. On average, it happens every 200k - 300k years, so animals have
experienced this many times.

I'm guessing there's a lot of initial confusion, but that they become
accustomed to the new orientation, once they associate a direction with
whatever sense they have of the magnetic field.

