Astronomy Without A Telescope – Animal Astronomy

Article written: 3 Jul , 2010
Updated: 24 Dec , 2015
by

[/caption]

In the 1950s, the Sauer research team locked some birds in Olbers planetarium and started messing with them. First they projected a northern hemisphere autumn sky and the birds flew ‘south’ – away from Polaris and keeping Betelgeuse to the left (‘east’). Then they projected a spring night sky and the birds flew ‘north’ towards Polaris with Betelgeuse again to their left, albeit this time in the ‘west’. The position of Betelgeuse appeared to be significant, perhaps because it’s one of the brighter stars in the northern hemisphere and just to the north of the celestial equator.

Later experiments with Indigo Buntings demonstrated that birds raised with no experience of the night sky didn’t have a clue what to do when released into a planetarium. However, birds that were raised with the night sky visible would fly ‘south’ away from the sky’s axis of rotation, whether that was Polaris or an artificial arbitrary axis created within the planetarium.

From this work, researchers concluded that it was unlikely that birds were born with a genetic star map, but instead learned to orientate themselves with respect to the rotating night sky by reference to other directional cues – like the position of the Sun and the Earth’s magnetic field.

It’s thought that many migratory birds closely monitor sunrise and sunset – allegedly when you see a line of birds on a power line, most will be facing east in the morning and west in the evening, recalibrating their internal compasses. Checking for a north-south plane of polarized light at sunrise and sunset may help them determine their latitude – by indicating how far off due east or west the Sun is when it’s at the horizon.

Pigeons have well developed magnetoreception that they can use as an alternative to solar navigation. For example, they can ‘home’ even with a heavily overcast sky – but get them to wear a little magnetized helmet that screws up their perception of the Earth’s magnetic field and they get lost. On the other hand, if it’s a clear day with the Sun visible they can find home just fine – even with a little magnetized helmet on.

As well as the birds – bacteria, bees, termites, lobsters, salamanders, salmon, turtles, mole rats and bats have all been shown to possess magnetoreception.

Magnetotactic bacteria manufacture their own magnetite crystals – building chains of crystals that mimic a compass needle. The bacteria appear to use their magnetite crystals for the simple purpose of determining which way is down – since a straight line to magnetic north will pass through the Earth’s surface.

Magnetospirillum with a line of synthesized magnetite crystals visible. Credit: www.microbiologybytes.com

It’s yet to be determined how a complex nervous system might interface with magnetite or whether magnetite is the primary mechanism in larger multicellular animals. Magnetite crystals have been isolated from bees and termites – and are apparently synthesized by them. However, in larger animals it’s harder to tell – as these crystals are tiny and difficult to find or visualize in vivo. An alternate magnetoreception mechanism based on photochemicals in the retina has been proposed for migratory birds – although a role for magnetite, particularly in pigeons which have relatively large concentrations of it in their beaks, can’t be ruled out.

Humans have traces of magnetite in their brains – although the court is still out on whether this gives us any capacity for direction finding by magnetoreception. Some research suggests a few individuals may have some very minor ability – but not enough for anyone to consider preferring this to their GPS.



15 Responses

  1. Member
    Aqua says

    I once had two green Indian Ring Necked Parakeets. Their names were Orville and Wilbur. They were interbred birds because the original owner wanted a BLUE Indian Ring Necked Parakeet which are highly sought after and very valuable. Due to in-breeding, Orville had a mild case of epilepsy. Wilbur found out that when Orville was asleep, if he pecked at Orville’s toes, Orville would awaken in an epileptic fit and fall to the bottom of the cage. When Wilbur did this, he would remove himself to a far part of the cage and watch…. and I’d swear, he’d laugh – some great sport, eh?

    The reason I’m telling this story is to make the following statement. NEVER underestimate SPIRIT in a body, as intelligence is subjective. Birds, Bee’s and even Tree’s and bacterium seem to know things which appear beyond their capacity, and yet… there it is. It doesn’t stop there. Micro-organisms have been shown to not only have a sense of direction, but also a purpose in their movements… so it seems reasonable that they would know which direction they were heading by whatever ‘compass’.

    I posit it is WE, who have lost our sense of direction and that is why we are so fascinated by those circumstances in nature.

    The leader of the Lakota Dakota Nakota Oyate, the Great Souix nation, Chief Arvol Looking Horse said, “A man or woman without SPIRIT is very dangerous. The absence of SPIRIT is causing suffering everywhere. We don’t want to believe we are in a time of survival because we have forgotten our spirits. The absence of spirit is causing suffering everywhere. We have forgotten that Grandmother Earth has a spirit. Disconnected souls are hurting others without even knowing they are hurting others – those hurt include animals, trees and waterways.”

  2. TerryG says

    Poor little animals. Thank you for your thoughtful description of getting Pigeons to “wear a little magnetized helmet that [temporarily] screws up their perception of the Earth’s magnetic field”. Is was a whole lot more bio-ethically acceptable than the University of Auckland’s approach which included electromagnetizing, anaesthetizing and finally severing the trigeminal and olfactory nerves to isolate how the poor little Pigeons brain was receiving the navigation data.

    Similar misgivings await any experimentalists that introduce a Magnetotactic gnome to Electrophorus electricus ( the Electric Eel). While this might theoretically induce more than the usual 500 volt shock if delivered the right kinematic lunge, the result would very likely degauss any magnetic memory potentially used for navigation. 🙁

  3. Silver Thread says

    I can very easily believe that more complex organisms retain an inherent ability to discern direction.

    I don’t think it works the way a compass does per se, but I have met and know quite a few avid outdoorsmen that have an uncanny direction sense, my father among them and to some degree myself as well.

    It’s not something you can learn or explain to someone without the ability and it sounds a bit metaphysical, but on a number of occasions I have found it to work quite well.

    Another odd aspect to it is that some geographical locales, for what ever reason, perhaps underlying geology, really screw with this mechanism.

  4. Lawrence B. Crowell says

    There was an article in Nature last year about possible quantum measurements of magnetic fields in birds.

    I question whether our urban scapes foul up the skys for birds with light pollution. Moths that fly around a light are confused into thinking they are following the moon. Sea turtles hone in with the moon and beach lights are now thought to confuse them.

    LC

  5. Emilio says

    As man developed as a hunter, tracking wide variety of animals in their seasonal migration, our internal magnetic direction finding must have become obsolete.

    It is the sense of time, direction and movement of planets that awaken us to consciousness of mathematics.

    All mans oldest monuments had to do with the tracking the sun and of spirit.

  6. Member

    @ Silver Thread & Emilio

    Yes, I think any experienced outdoors person would have a huge range of stimuli to choose from (position of the sun, lay of the land etc) to send them off in the right general direction until they get to a point where they could start picking up familiar landmarks and find their way home.

    It’s an interesting thought experiment to try and design an experiment that might effectively demonstrate whether or not humans have a (presumably exceedingly faint) degree of magnetoreception. It’s unlikely that anyone could instantly point to the socially constructed concept of North.

    Magnetoreception may just be a latent and very ancestral skill and there have not been any recent natural selection pressures on our species that might favor those individuals who could effectively navigate by this mechanism.

  7. Torbjorn Larsson OM says

    Oh poo! Here is a post that has opened a can of worms, and I have been entirely to negative here lately. Call me Mr Grumpy then, but a grump has to do what a grump has to do:

    Let me just note that I have no references to double blind experiments that unequivocally demonstrate direction finding in humans at sufficient certainty, and the article presents none. The several anecdotes given here are unfortunately precisely anecdote and not to be confused with data. Hopefully my negative outlook can be remedied.

    OTOH magnetotactic bacteria, a known phenomena, are positively fascinating! 🙂 Since cells and cell organelles grow in an “organic distribution” of a growth limit, while minerals grow from uncorrelated mechanisms in a log-normal distribution, one can feasibly test magnetites for biogenic/abiogenic progeny on a single trait.

    It was proposed to do so with the ALH84001 magnetites by Thomas-Keptra et al (after sorting for polycrystallites et cetera) ~2000 IIRC, but despite having a remaining 40-50 odd magnetites to test no quantitative test was ever done. Merely qualitative, and IMHO not persuasive, pattern matching of distributions, despite there existing statistical methods for testing of observing specific distributions (see for example Cosma Shalizi’s methods).

    Why that opportunity wasn’t taken care of, I don’t know. :- ( In this case I feel qualified in my grumpyness: maybe we would have learned something fantastic about life on Mars!

  8. TerryG says

    Q. So, could some of the great extinctions have been triggered by magneto-migratory species suddenly being confounded by geomagnetic reversals? :-0
    A. No. While such survival adaptations evolve over many generations, this is still fast enough for the 51 slowly occurring Geomagnetic reversals in the last 15 million years to have gone largely noticed. The Dinosaurs were still wiped out by an Asteroid.

  9. Member

    There’s some scant research on human magnetoreception mentioned here: http://en.wikipedia.org/wiki/Magnetoception#In_humans
    (but nothing very convincing).

  10. Emilio says

    Testing? I know a way. Just strap a subject on to a chair that can spin with wheels. Cover up his eye, ear with breathing apparatus over his mouth and nose. Give him a switch and a little poker for communication. None of the test apparatus on him should be magnetic though.

    Now we need two rooms; empty room and room with MRI. Shuffle him around from room to room, spin him, and ask if he is in the room with MRI or not and in which direction MRI sits after a spin. Some times MRI gets switched on some time not. Take data.

  11. Member

    @ Emilio

    OK, like it so far. But MRIs are expensive – couldn’t we just position a weaker magnet closer to his head?

    And although I’m all for research involving blindfolding people and strapping them to spinning chairs – some nay-sayers will probably argue that this would distract them from focusing on their magnetic sense.

    But I do like it so far.

  12. Torbjorn Larsson OM says

    Thanks, Steve!

    Well, that the first claims unsurprisingly “could not be reproduced” is likely due lacking double blinding (as in my suspicion), but I haven checked.

    That EM fields affect the brain, which is an electromotive function (neuron) machine, is no surprise either, but doesn’t bear much on the purported trait (again, haven’t checked).

    So nothing very convincing is a fair claim. 😀

    @ Emilio:

    That sounds more like it, in a nauseating (sorry) way. An MRI isn’t soundless, so I dunno if this could be made in a ‘blind’ (deaf) way, the magnets would likely be better.

    Also, it isn’t entirely double blind, which is essential to get away from the experimenters unconscious (or not!) suggestions or otherwise influencing results.

    Like this perhaps: Put your guy and many magnets in one room, randomly activating them without the experimenters knowing which one/ones until after?

    So what are we saying, this experimental area needs a sense of direction? 😮

  13. Torbjorn Larsson OM says

    Also, I think we can thank the “parapsychologists” for infecting the whole area of human experimenting with cherry-picking and non-blinded experiments. They are still at it, and there would be a very brave scientist trying to do something along those lines (show unexpected traits in humans) meanwhile.

    It will take generations before the memory fades. Assuming that they stop anytime soon, and we haven’t seen that yet …

  14. TerryG says

    Wouldn’t that make it CheepAstronomy?

  15. Paul Eaton-Jones says

    To Steve Nerlich.
    I too like the idea of strapping blindfolded people in spinning chairs! ;-). I have a number of candidates here at my school who I’d gladly volunteer if you decide to go ahead.

Comments are closed.