How do animals & bacteria sense compass direction?

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SUMMARY

The discussion centers on the mechanisms by which animals and certain bacteria sense compass direction, primarily through the incorporation of magnetite, a ferromagnetic material. Species such as migratory birds, honey bees, sharks, and bacteria like Magnetospirillum gryphiswaldense utilize magnetite for spatial orientation. Research indicates that magnetite crystals in these organisms may act as receptors that relay directional information to the brain, allowing for navigation based on Earth's magnetic field. The bobolink is highlighted as a notable example of this phenomenon, with studies suggesting that its brain cells contain magnetite that aligns with magnetic north.

PREREQUISITES
  • Understanding of magnetoreception in animals
  • Basic knowledge of biochemistry related to magnetite
  • Familiarity with neuroethology and brain function in navigation
  • Awareness of migratory patterns in various species
NEXT STEPS
  • Research the role of magnetite in animal navigation
  • Explore the neuroethological mechanisms of magnetoreception
  • Investigate the specific adaptations of migratory birds like the bobolink
  • Study the implications of magnetite in bacteria such as Magnetospirillum gryphiswaldense
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Biologists, neuroethologists, ecologists, and anyone interested in the mechanisms of animal navigation and magnetoreception.

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You are probably aware of migratory behavior of birds. But what is the mechanism that accounts for this?

It is based on a unique biochemistry that incorporates ferromagnetic material (magnetite) within them and utilizes their orientation to govern its spatial movement (horizontal and vertical). Outside of migration behavior, other examples of orientation behavior due to magnetite, occur across the animal kingdom: honey bees, homing pigeons, sharks, dolphins, newt, rainbow trout, salmon. Even certain bacteria e.g. Magnetospirillum gryphiswaldense exhibit this. Researchers found stable needle-like strands of magnetite crystal (magnetic dipoles) in these bacteria.
 
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Biology news on Phys.org
here is an interesting article that addresses "Navigating With A Built-In Compass":
http://www.nwf.org/nationalwildlife/article.cfm?articleId=682&issueId=26
 
gerben said:
here is an interesting article that addresses "Navigating With A Built-In Compass":
http://www.nwf.org/nationalwildlife/article.cfm?articleId=682&issueId=26
Nice one gerben! The bobolinks (and a few other species) sure have evolved quite an impressive mechanism for direction finding :biggrin:

So the hundred dollar question is, how does the magnetite interface with the brain, so that it senses magnetic polar direction? Does the brain compare magnetic field to a spatial map comprised of brain cells? :rolleyes:

Do we have any neuroethologists here on PF?

Quote from gerben's http://www.nwf.org/nationalwildlife/article.cfm?articleId=682&issueId=26:
"Like any good pilot, the bobolink carries a compass. Recent research suggests that cells in the bird's head contain magnetite, an iron oxide crystal that aligns with magnetic north like a tiny compass needle. Scientists think these cells may serve as receptors that send directional information to the brain. Many other animals apparently also have such cells: Magnetite has been found in the heads of migratory fish, sea turtles and humpback whales. Of all the wildlife navigators, birds so far are the best studied."
 
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