4 ms·

A study on how turtles navigate using the Earth’s magnetic field

166 points by gmays 2y ago

actinium226 2y ago
At first I thought this was a mnemonic and then I quickly realized that DTUSD is probably not something people try to remember
crazydoggers 2y ago
I wonder if it’s actually a form of touch sensation. Some parts of the body might be minutely susceptible to magnetic fields and the feeling is distributed across areas of the turtle. The human finger can sense things only a micron in size. Something like miniscule tugging of the shell in certain directions being felt?
- adrian_b 2y ago
  In some living beings it is known that they sense the magnetic field with microscopic magnetite crystals (i.e. iron oxide, Fe3O4), that are inside some cells. The magnetic field is sensed by the magnetic forces that act on the magnetite crystals, much in the same way as we sense gravity and acceleration by the forces that act on the otoliths in our inner ear. While in turtles it has not been identified how they sense the magnetic field, one of the possibilities is that they also use magnetite crystals located somewhere, at least for one of the two kinds of magnetic senses identified in them.
hammock 2y ago
Very cool. So they have a map sense, and a compass sense, and we don’t know how either of them work still.
- stevenwoo 2y ago
  There are tracking studies on some of the turtles that navigate from Gulf of Mexico to Atlantic and back that appear to know where the favorable currents are so there is alot of genetic memory like the Monarch butterfly migrations taking multiple generations to get from North America to Mexico.
shellfishgene 2y ago
Is there really not a single link to the actual paper in the press release or did I just miss it?
- ysofunny 2y ago
  there's only a link to the lab (that I was able to find) https://lohmannlab.web.unc.edu/ https://lohmannlab.web.unc.edu/
- throwaway1 2y ago
  Goforth, K. M., Lohmann, C. M. F., Gavin, A., Henning, R., Harvey, A., Hinton, T. L., Lim, D. S., and Lohmann, K. J. Learned magnetic map cues and two mechanisms of magnetoreception in turtles. Nature (2025). https://doi.org/10.1038/s41586-024-08554-y https://doi.org/10.1038/s41586-024-08554-y https://www.nature.com/articles/s41586-024-08554-y https://www.nature.com/articles/s41586-024-08554-y Full text: https://rdcu.be/d9CgI https://rdcu.be/d9CgI (shortened link as provided on the page below) ( Provided by the lab's 'Publications' page: https://lohmannlab.web.unc.edu/research-publications/ https://lohmannlab.web.unc.edu/research-publications/ )
tombert 2y ago
Turtles are my favorite animals (other than humans, and sometimes even more than them). Mostly I think they're just cute, which is by itself a perfectly valid reason for an animal to be your favorite, but I've always been fascinated by their ruggedness. It's not weird for a turtle to live to 100 years old, and it feels like they can survive just about anything. Having a built-in GPS just makes them even cooler.
- pak9rabid 2y ago
  I like turtles
  - treebeard901 2y ago
    It's turtles all the way down
    - carrozo 2y ago
      oh. more turtles.
- joshuaturner 2y ago
  I just find their karate abilities quite remarkable
Biologist123 2y ago
My old man - an old-fashioned cat by anyone’s description — can pick true north anytime, anywhere. It’s made me wonder if he has some kind of internal magnetic compass. And now, having read this, I wonder if this ‘turtle skill’ is latent in humans but only emerges in a rare few.
- pinoy420 2y ago
  Can he notice when it shifts? What happens when the magnetic field flips?
- swores 2y ago
  You maybe meant "magnetic north", not "true north"? Or if you meant what you wrote, then fairly safe to rule out magnetism from being involved! (I suspect it's not involved either way, but I don't know anything) (Explanation of the difference between true and magnetic norths: https://www.rmg.co.uk/stories/topics/true-north-magnetic-north-whats-difference https://www.rmg.co.uk/stories/topics/true-north-magnetic-nor... )
- blueflow 2y ago
  I can sense magnetic fields of some strength through my nasal bone. Its like a metallic taste except its not where your taste buds are. I don't know if its rare? I think most people just never held a magnet against their face.
  - Retric 2y ago
    People get exposed to extremely strong magic fields when getting an MRI. So that’s probably not it.
    - daveguy 2y ago
      On the surface this looks like a non-sequitur. I'm not sure what people getting exposed to strong magnetic fields while getting an MRI has to do with detecting a magnetic field. Are you saying something like "we should have been able to detect this"? This doesn't seem correct to me, because the magnetic field is through the aperture of the MRI -- ie head to toe in most MRI applications. If the MRI field is orthogonal to earth's typical magnetic pole, you wouldn't expect the same signal. I'm skeptical of a claim from a person that they can "detect" the earth's magnetic field, but I don't think "we have MRIs" implies anything about that ability.
pinoy420 2y ago
It explains the phenomena and the response but not the mechanism. Anyone know?
trhway 2y ago
>But no receptor like that has been identified for the magnetic sense, and the mechanism remains unknown Wasn’t such a molecule found in bird’s eyes?
- defanor 2y ago
  It is one of the proposed mechanisms, but apparently it is still unclear what is actually used [1,2]. [1] https://en.wikipedia.org/wiki/Magnetoreception#Proposed_mechanisms https://en.wikipedia.org/wiki/Magnetoreception#Proposed_mech... [2] https://www.scientificamerican.com/article/how-migrating-birds-use-quantum-effects-to-navigate/ https://www.scientificamerican.com/article/how-migrating-bir...
PicassoCTs 2y ago
So if the poles flip- there navigation fails?
nashashmi 2y ago
I wonder if bats have the same senses to magnetic field.
rapind 2y ago
More proof we’re just flying around on the back of a turtle on the back of a turtle…
acyou 2y ago
When they first figured out that turtles use magnetic fields to navigate, they placed them in kiddie swimming pools in someone's backyard and placed large electromagnets next to the swimming pools. Multiple turtles reliably oriented themselves according to the magnetic field direction corresponding with their seasonal migration direction. This paper is claiming something different, something to do with a particular magnetic field having a behavioral association. Lot of question marks and need for some more context. Why would turtles evolve the dancing behavior? Does it have to do with the kind of food they eat and how they get that food? No, turtles did not evolve like dogs to dance and do tricks for food.
- gwerbret 2y ago
  > Multiple turtles reliably oriented themselves according to the magnetic field direction corresponding with their seasonal migration direction. This paper is claiming something different, something to do with a particular magnetic field having a behavioral association. The paper (which is here [0] by the way, they failed to provide a link in the article) indicates that these turtles have been known to orient themselves using magnetic fields. The new finding is that they're also able to use magnetic fields as a map -- they can identify a location based on its specific magnetic fields. And apparently, the "mapping" involves a different neurobiological mechanism from the "orientation". 0: https://www.nature.com/articles/s41586-024-08554-y https://www.nature.com/articles/s41586-024-08554-y
aaron695 2y ago
[dead]
wkyleg 2y ago
Interesting that they don't know exactly how they are perceiving magnetism. I suppose it could be an internal brain mechanism, but if that were to be able to operate without direct outside sensory input, there might be all kinds of other potential latent abilities in animals. More likely, this might be the same as the mechanism which exists in birds, who can effectively see the Earth's magnetic field in their eyes, although an internal magnetic detection system present in animals would be much more interesting. See https://royalsocietypublishing.org/doi/10.1098/rsif.2019.0295 https://royalsocietypublishing.org/doi/10.1098/rsif.2019.029.... Birds essentially perceive the Earth's magnetic field through a chemical process in the receptors for red and green light in their eyes, and are believed to have special cells in their beak, brain stem, and possibly their vestibular system as well. It can be disrupted fairly easy by magnetism or different wavelengths of light. There are obvious other strange implications of this as well, although I'm not sure how much real evidence there is to support them. For instance, there are many concerns about the effects of EMF exposure, as well as that EMF can affect plant life. There is research on magnetic and electric brain stimulation as well. At the most out-there level, there is the research into remote viewing and things like telepathy. So, to whatever extent this actually exists, there are interesting implications for the phenomenological experience of other forms of animal life. Regardless, it is interesting to see research that is actually showing new and intriguing things regarding different forms of perception (I guess this is arguably ESP, or at least a new sense) that are not complete crank nonsense. I've always felt like my sense of direction was a sort of 6th sense; I guess it really could be.
samldev 2y ago
Go Heels!
dahart 2y ago
> “The big question is always the mechanism,” Goforth said. “What’s the mechanism and what is the sensor? We know that for the visual sense, you have eyes; for the sense of smell, you have a nose; and for hearing, you have ears. But no receptor like that has been identified for the magnetic sense, and the mechanism remains unknown.” Interesting, I just barely listened to a Radiolab episode about magnetoreception in birds today [1]. The mechanism is thought to be cryptochrome, a type of protein that exhibits quantum effects when exposed to blue light [2]. The RadioLab story mentioned this mechanism was first proposed in the 70s (I think?) and it was heresy at the time a didn’t get published. Now there’s a SciAm article about it [3], and lots of blog posts. I wonder why this isn’t mentioned? Isn’t there a pretty good chance the mechanism is the same? * edit: BTW while listening to the podcast I was reminded of Haidinger’s Brush [4] - the fact that many humans can see polarization, once they know what to look for. I wonder if it’s potentially related to navigation since the polarization effect is strongest at 90 degrees from the sun… i.e., generally north and south, in the morning and evening, for much of the earth. [1] https://radiolab.org/podcast/quantum-birds https://radiolab.org/podcast/quantum-birds [2] https://en.wikipedia.org/wiki/Cryptochrome#Magnetoreception https://en.wikipedia.org/wiki/Cryptochrome#Magnetoreception [3] https://www.scientificamerican.com/article/how-migrating-birds-use-quantum-effects-to-navigate/ https://www.scientificamerican.com/article/how-migrating-bir... [4] https://en.wikipedia.org/wiki/Haidinger's_brush https://en.wikipedia.org/wiki/Haidinger's_brush
tydes 2y ago
I could have sworn I remember hearing this a few years back & that it was discovered due to the increase in shifting of magnetic north over time, & that their migrations back home correlated in that they were off by that amount.. At least that's what I've been telling folk. NewScientist I'm certain.
deleted 2y ago
[deleted]
deleted 2y ago
[deleted]

166 points by gmays 2y ago

At first I thought this was a mnemonic and then I quickly realized that DTUSD is probably not something people try to remember

crazydoggers 2y ago

I wonder if it’s actually a form of touch sensation. Some parts of the body might be minutely susceptible to magnetic fields and the feeling is distributed across areas of the turtle. The human finger can sense things only a micron in size. Something like miniscule tugging of the shell in certain directions being felt?

adrian_b 2y ago
In some living beings it is known that they sense the magnetic field with microscopic magnetite crystals (i.e. iron oxide, Fe3O4), that are inside some cells. The magnetic field is sensed by the magnetic forces that act on the magnetite crystals, much in the same way as we sense gravity and acceleration by the forces that act on the otoliths in our inner ear. While in turtles it has not been identified how they sense the magnetic field, one of the possibilities is that they also use magnetite crystals located somewhere, at least for one of the two kinds of magnetic senses identified in them.

hammock 2y ago

Very cool. So they have a map sense, and a compass sense, and we don’t know how either of them work still.

stevenwoo 2y ago
There are tracking studies on some of the turtles that navigate from Gulf of Mexico to Atlantic and back that appear to know where the favorable currents are so there is alot of genetic memory like the Monarch butterfly migrations taking multiple generations to get from North America to Mexico.

shellfishgene 2y ago

Is there really not a single link to the actual paper in the press release or did I just miss it?

ysofunny 2y ago
there's only a link to the lab (that I was able to find) https://lohmannlab.web.unc.edu/ https://lohmannlab.web.unc.edu/
throwaway1 2y ago
Goforth, K. M., Lohmann, C. M. F., Gavin, A., Henning, R., Harvey, A., Hinton, T. L., Lim, D. S., and Lohmann, K. J. Learned magnetic map cues and two mechanisms of magnetoreception in turtles. Nature (2025). https://doi.org/10.1038/s41586-024-08554-y https://doi.org/10.1038/s41586-024-08554-y https://www.nature.com/articles/s41586-024-08554-y https://www.nature.com/articles/s41586-024-08554-y Full text: https://rdcu.be/d9CgI https://rdcu.be/d9CgI (shortened link as provided on the page below) ( Provided by the lab's 'Publications' page: https://lohmannlab.web.unc.edu/research-publications/ https://lohmannlab.web.unc.edu/research-publications/ )

tombert 2y ago

Turtles are my favorite animals (other than humans, and sometimes even more than them). Mostly I think they're just cute, which is by itself a perfectly valid reason for an animal to be your favorite, but I've always been fascinated by their ruggedness. It's not weird for a turtle to live to 100 years old, and it feels like they can survive just about anything. Having a built-in GPS just makes them even cooler.

pak9rabid 2y ago
I like turtles
- treebeard901 2y ago
  It's turtles all the way down
  - carrozo 2y ago
    oh. more turtles.
joshuaturner 2y ago
I just find their karate abilities quite remarkable

Biologist123 2y ago

My old man - an old-fashioned cat by anyone’s description — can pick true north anytime, anywhere. It’s made me wonder if he has some kind of internal magnetic compass. And now, having read this, I wonder if this ‘turtle skill’ is latent in humans but only emerges in a rare few.

pinoy420 2y ago
Can he notice when it shifts? What happens when the magnetic field flips?
swores 2y ago
You maybe meant "magnetic north", not "true north"? Or if you meant what you wrote, then fairly safe to rule out magnetism from being involved! (I suspect it's not involved either way, but I don't know anything) (Explanation of the difference between true and magnetic norths: https://www.rmg.co.uk/stories/topics/true-north-magnetic-north-whats-difference https://www.rmg.co.uk/stories/topics/true-north-magnetic-nor... )
blueflow 2y ago
I can sense magnetic fields of some strength through my nasal bone. Its like a metallic taste except its not where your taste buds are. I don't know if its rare? I think most people just never held a magnet against their face.
- Retric 2y ago
  People get exposed to extremely strong magic fields when getting an MRI. So that’s probably not it.
  - daveguy 2y ago
    On the surface this looks like a non-sequitur. I'm not sure what people getting exposed to strong magnetic fields while getting an MRI has to do with detecting a magnetic field. Are you saying something like "we should have been able to detect this"? This doesn't seem correct to me, because the magnetic field is through the aperture of the MRI -- ie head to toe in most MRI applications. If the MRI field is orthogonal to earth's typical magnetic pole, you wouldn't expect the same signal. I'm skeptical of a claim from a person that they can "detect" the earth's magnetic field, but I don't think "we have MRIs" implies anything about that ability.

pinoy420 2y ago

It explains the phenomena and the response but not the mechanism. Anyone know?

trhway 2y ago

>But no receptor like that has been identified for the magnetic sense, and the mechanism remains unknown Wasn’t such a molecule found in bird’s eyes?

defanor 2y ago
It is one of the proposed mechanisms, but apparently it is still unclear what is actually used [1,2]. [1] https://en.wikipedia.org/wiki/Magnetoreception#Proposed_mechanisms https://en.wikipedia.org/wiki/Magnetoreception#Proposed_mech... [2] https://www.scientificamerican.com/article/how-migrating-birds-use-quantum-effects-to-navigate/ https://www.scientificamerican.com/article/how-migrating-bir...

PicassoCTs 2y ago

So if the poles flip- there navigation fails?

nashashmi 2y ago

I wonder if bats have the same senses to magnetic field.

rapind 2y ago

More proof we’re just flying around on the back of a turtle on the back of a turtle…

acyou 2y ago

When they first figured out that turtles use magnetic fields to navigate, they placed them in kiddie swimming pools in someone's backyard and placed large electromagnets next to the swimming pools. Multiple turtles reliably oriented themselves according to the magnetic field direction corresponding with their seasonal migration direction. This paper is claiming something different, something to do with a particular magnetic field having a behavioral association. Lot of question marks and need for some more context. Why would turtles evolve the dancing behavior? Does it have to do with the kind of food they eat and how they get that food? No, turtles did not evolve like dogs to dance and do tricks for food.

gwerbret 2y ago
> Multiple turtles reliably oriented themselves according to the magnetic field direction corresponding with their seasonal migration direction. This paper is claiming something different, something to do with a particular magnetic field having a behavioral association. The paper (which is here [0] by the way, they failed to provide a link in the article) indicates that these turtles have been known to orient themselves using magnetic fields. The new finding is that they're also able to use magnetic fields as a map -- they can identify a location based on its specific magnetic fields. And apparently, the "mapping" involves a different neurobiological mechanism from the "orientation". 0: https://www.nature.com/articles/s41586-024-08554-y https://www.nature.com/articles/s41586-024-08554-y

aaron695 2y ago

[dead]

wkyleg 2y ago

Interesting that they don't know exactly how they are perceiving magnetism. I suppose it could be an internal brain mechanism, but if that were to be able to operate without direct outside sensory input, there might be all kinds of other potential latent abilities in animals. More likely, this might be the same as the mechanism which exists in birds, who can effectively see the Earth's magnetic field in their eyes, although an internal magnetic detection system present in animals would be much more interesting. See https://royalsocietypublishing.org/doi/10.1098/rsif.2019.0295 https://royalsocietypublishing.org/doi/10.1098/rsif.2019.029.... Birds essentially perceive the Earth's magnetic field through a chemical process in the receptors for red and green light in their eyes, and are believed to have special cells in their beak, brain stem, and possibly their vestibular system as well. It can be disrupted fairly easy by magnetism or different wavelengths of light. There are obvious other strange implications of this as well, although I'm not sure how much real evidence there is to support them. For instance, there are many concerns about the effects of EMF exposure, as well as that EMF can affect plant life. There is research on magnetic and electric brain stimulation as well. At the most out-there level, there is the research into remote viewing and things like telepathy. So, to whatever extent this actually exists, there are interesting implications for the phenomenological experience of other forms of animal life. Regardless, it is interesting to see research that is actually showing new and intriguing things regarding different forms of perception (I guess this is arguably ESP, or at least a new sense) that are not complete crank nonsense. I've always felt like my sense of direction was a sort of 6th sense; I guess it really could be.

samldev 2y ago

Go Heels!

dahart 2y ago

> “The big question is always the mechanism,” Goforth said. “What’s the mechanism and what is the sensor? We know that for the visual sense, you have eyes; for the sense of smell, you have a nose; and for hearing, you have ears. But no receptor like that has been identified for the magnetic sense, and the mechanism remains unknown.” Interesting, I just barely listened to a Radiolab episode about magnetoreception in birds today [1]. The mechanism is thought to be cryptochrome, a type of protein that exhibits quantum effects when exposed to blue light [2]. The RadioLab story mentioned this mechanism was first proposed in the 70s (I think?) and it was heresy at the time a didn’t get published. Now there’s a SciAm article about it [3], and lots of blog posts. I wonder why this isn’t mentioned? Isn’t there a pretty good chance the mechanism is the same? * edit: BTW while listening to the podcast I was reminded of Haidinger’s Brush [4] - the fact that many humans can see polarization, once they know what to look for. I wonder if it’s potentially related to navigation since the polarization effect is strongest at 90 degrees from the sun… i.e., generally north and south, in the morning and evening, for much of the earth. [1] https://radiolab.org/podcast/quantum-birds https://radiolab.org/podcast/quantum-birds [2] https://en.wikipedia.org/wiki/Cryptochrome#Magnetoreception https://en.wikipedia.org/wiki/Cryptochrome#Magnetoreception [3] https://www.scientificamerican.com/article/how-migrating-birds-use-quantum-effects-to-navigate/ https://www.scientificamerican.com/article/how-migrating-bir... [4] https://en.wikipedia.org/wiki/Haidinger's_brush https://en.wikipedia.org/wiki/Haidinger's_brush

tydes 2y ago

I could have sworn I remember hearing this a few years back & that it was discovered due to the increase in shifting of magnetic north over time, & that their migrations back home correlated in that they were off by that amount.. At least that's what I've been telling folk. NewScientist I'm certain.

deleted 2y ago

[deleted]

deleted 2y ago

[deleted]