Magnetism the 6th Sense. Do Humans Have It?

Dotini

* Dozens of animal species, from ants to whales, have well-documented abilities to detect the geomagnetic field and use it for orientation and navigation.
* After some false starts, researchers may have now located the organs for this magnetic sense, and they are finally understanding the physics that underpins it.
* Some animals may use microscopic magnetic particles to detect magnetic fields; others might harness quantum effects on certain pigments in the eye.

For what must have felt like an interminable six months back in 2007, Sabine Begall spent her evenings at her computer, staring at photographs of grazing cattle. She would download a satellite image of a cattle range from Google Earth, tag the cows one by one, then pull up the next image. With the help of her collaborators, Begall, a zoologist at the University of Duisburg-Essen in Germany, ultimately found that the unassuming ruminants were on to something. On average, they appeared to align their bodies with a slight preference toward the north-south axis. But they were not pointing to true north, which they could have located using the sun as reference. Instead they somehow knew how to orient themselves toward the magnetic north pole, which is hundreds of kilometers south of the geographic pole, in northern Canada.
http://www.scientificamerican.com/ar...compass-within

Can anyone doubt this?
Alternatively, can anyone back this up with any remotely credible anecdotal evidence?

Respectfully submitted,
Steve

Evo

I have seen cattle grazing and they tend to be in all directions. Now, moving as a herd, they all go in one direction, and can even have a routine. Cows next door to my grandmother's would be taken to their pasture in the morning and immediately head east to the opposite end and then eat their way back to the gates (west) by late afternoon.

This is what a typical grazing herd looks like.

Ryan_m_b

Is there a paper with some statistical analysis? Any data? Discussion of possible causes? It's one thing to observe that cows in a particular herd under a certain span of time tend to orientate themselves towards magnetic north, it's another entirely to suggest that they have magnetoreceptors of some kind.

D H

This appears to be the article in question:

Sabine Begall, Jaroslav Červený, Julia Neef, Oldřich Vojtěch, and Hynek Burda, Magnetic alignment in grazing and resting cattle and deer, PNAS 2008 105 (36) 13451-13455
http://www.pnas.org/content/105/36/13451

Evo

They only looked at photos.

The paper states http://www.pnas.org/content/early/20....full.pdf+html

Ivan Seeking

I'm confused. Are you implying that the study isn't valid?

Evo

I'm stating what is said in the report in answer to Ryan's question.

They don't show any of the pictures. We don't know if terrain had any impact, we really know nothing other than she deduced from looking at a bunch of google photos that a lot of cows seem to prefer a north/south orientation. But for how long at a time? Same cows every day? Same part of the pasture?

And they say that no one watching over the herds had ever noticed. I would think if all cows aligned all or most of the day, every day, over a thousand years, someone might have noticed.

Also, wind direction for the cows is unknown, so could be a factor in the pictures she chose. The only study they did that took wind into consideration was on red and roe deer data, not cattle.

Ryan_m_b

I have taken a brief look at the study and a few things spring to mind. Firstly they are taking a purely static shot compiled by random shots of cattle on Google Earth (which is notorious for stitching together satellite pictures in odd ways; I'm not sure if or how this would affect the study though). There is no observation over time nor can any confounding variables properly be teased out, they claim to have only included flat ground, taken shots from the same time of day and resolved body direction but I am sceptical of all of this (especially as they admit that they cannot resolve which is the head and which is the tail of the organism which leads me to wonder how they even know it's a cow or doe).

I'd like to see a more controlled study on this looking at particular herds that can be characterised and monitored over time. I also wonder how much confirmation bias came into this i.e. how many pictures of cattle were excluded because the researcher looking for them thought they looked too random (this isn't an accusation of foul play but even subconsciously a person might dismiss a picture because it doesn't conform to the previous data set and pass it off as "it's too close to a town" or "it's not flat ground" even though other pictures suffer from this complaint more).

Dotini

So is it settled, or is it not, that some animal species have the (sixth) sense of magnetism?
Is there an inherent anatomical reason why humans could not or should not share this sense with other species?

Respectfully submitted,
Steve

FlexGunship

Should be easy enough to test much better than the study provided shows. This isn't significantly better than armchair science.

If you simply attached small digital compasses to cows all over the world (remember, a digital compass will fit inside a cell phone without problem) and align it to the cow it's just a matter of recording over time. A plot of angle vs. duration would be enough to settle this conclusively. Do cows (in general) spend more time facing magnetic north?

Alternatively, you could place a cow directly on the magnetic north pole and see if he or she spins violently.


I don't think there's any reason to disbelieve that some animals have a "magnetic sense." However, the study posted in this thread is not strong evidence for it.

Humans would probably be less likely to have this sense evolutionary speaking because, as a species, we have not had a migratory tendency which would necessitate it for survival purposes. Furthermore, looking through human history, migration doesn't seem to be strongly unidirectional or unilateral. And, lastly, the average tourist in New Hampshire clearly has absolutely *no* sense of direction; the average error of an ocean-seeking individual and a mountain-seeking individual seem to be equal.

Ryan_m_b

Magnetoreception is a well established phenomenon, unless there have been some breakthrough studies in recent years I'm unaware of it has never been confirmed in a mammal and from this data we cannot conclude that magnetoception has been confirmed in mammals; more study needs to be done. As for why humans could not have it there is no reason, should not have it is that we haven't seen any evidence for it nor any evidence that similar related species in our evolutionary lineage have the trait nor an explanation of why it should evolve in our history.

Also the whole "five senses" thing is a myth, it's closer to 15 in humans depending on definition.

FlexGunship

I'm going to tell everyone that I have a 6th sense, now... when they ask what it is, I'll tell them: "I can sense when I need to vomit."

Sigh...

EDIT: Incidentally, there is some anecdotal evidence that individuals are susceptible to electromagnetic radiation.

http://en.wikipedia.org/wiki/Electro...persensitivity

NOTE: No test has been done, that I know of, where these "EM-sensitive" individuals, instead it seems that its a psychosomatic effect. In presence of a working cell-phone they experience extreme pain and discomfort which is alleviated when the phone's battery is removed, yet they cannot (in a double-blind test) differentiate between a cell-phone that is on or off.

Ryan_m_b

Or "for my 6th sense I can sense pain and you're being a huge one in my a***"

FlexGunship

That post was so bad that it stimulated my 7th sense, the sensory receptors in my pharynx mucosa, and made me gag.

Ryan_m_b

The sensory input I'm receiving from my pulmonary stretch receptors in conjunction with my mechano- and proprioception senses are telling me to desist from this jovial activity, stop laughing and get up off of the floor

FlexGunship

Oh please, your 9th sense, you rectal stretch receptors, must be triggering because you're clearly full of s***.

EDIT: I'm just smellin' an infraction.

AlephZero