Pigeons Have Magnets

Walcott, Charles D.; Gould, James L.; Kirschvink, Joseph L.

doi:10.1126/science.472725

Cited by 270 publications

(115 citation statements)

References 15 publications

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“…This ability is dependent upon the intracellular biomineralization of magnetic particles and the formation of organic compartments or vesicles; this magnetic field sensing behavior can be found in a diversity of organisms (Lowenstam, 1981). For example, Gould et al (1978) discovered that honeybees contain magnetite localized in their abdomen, and Walcott and colleagues (Walcott, 1977;Walcott et al, 1979) discovered magnetite in the head of homing pigeons. Among other eukaryotic organisms in which magnetite has been experimentally found are fish (Mann et al, 1988;Diebel et al, 2000) and termites (Maher 1998).…”

Section: Introductionmentioning

confidence: 99%

Sudden motility reversal indicates sensing of magnetic field gradients in Magnetospirillum magneticum AMB-1 strain

et al. 2014

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Many motile unicellular organisms have evolved specialized behaviors for detecting and responding to environmental cues such as chemical gradients (chemotaxis) and oxygen gradients (aerotaxis). Magnetotaxis is found in magnetotactic bacteria and it is defined as the passive alignment of these cells to the geomagnetic field along with active swimming. Herein we show that Magnetospirillum magneticum (AMB-1) show a unique set of responses that indicates they sense and respond not only to the direction of magnetic fields by aligning and swimming, but also to changes in the magnetic field or magnetic field gradients. We present data showing that AMB-1 cells exhibit sudden motility reversals when we impose them to local magnetic field gradients. Our system employs permalloy (Ni 80 Fe 20 ) islands to curve and diverge the magnetic field lines emanating from our custom-designed Helmholtz coils in the vicinity of the islands (creating a drop in the field across the islands). The three distinct movements we have observed as they approach the permalloy islands are: unidirectional, single reverse and double reverse. Our findings indicate that these reverse movements occur in response to magnetic field gradients. In addition, using a permanent magnet we found further evidence that supports this claim. Motile AMB-1 cells swim away from the north and south poles of a permanent magnet when the magnet is positioned less than B30 mm from the droplet of cells. All together, these results indicate previously unknown response capabilities arising from the magnetic sensing systems of AMB-1 cells. These responses could enable them to cope with magnetic disturbances that could in turn potentially inhibit their efficient search for nutrients.

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Section: Introductionmentioning

confidence: 99%

Sudden motility reversal indicates sensing of magnetic field gradients in Magnetospirillum magneticum AMB-1 strain

et al. 2014

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“…Biomineralization of strongly magnetic ferrimagnets, such as magnetite (Fe 3 O 4 ), has been reported for an extremely diverse range of organisms, from single-celled bacteria (Blakemore 1982) to algae (Lins de Barros et al 1981), honeybees (Gould et al 1978), butter£ies (MacFadden & Jones 1985), ¢sh (including salmon (Kirschvink et al 1985)), birds (especially homing pigeons (Walcott et al 1979)) and mammals, including humans (Kirschvink 1981;Schultheiss-Grassi et al 1997). Active formation of ferrimagnets by organisms has been ascribed direct ecological advantages, in terms of the possibility of geomagnetic-assisted motility (as, for example, in the case of magnetotactic bacteria), or navigation (as in salmon and homing pigeons).…”

Section: Introductionmentioning

confidence: 99%

Magnetite biomineralization in termites

Maher

1998

Proc. R. Soc. Lond. B

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Experimental evidence exists for magnetoreception in termites, a major component of the soil macrofauna in many tropical countries. This preliminary study identi¢es, probably for the ¢rst time, the presence of biogenic ferrimagnets (magnetite?) in two species of termite (Nasutitermes exitiosus and Amitermes meridionalis), based on magnetic measurements of whole termite specimens and individual body sections, and analysis by electron microscopy of magnetically extracted grains. The magnetic measurements indicate the presence of very small concentrations of magnetic material, with more magnetic grains in the thorax and abdomen region compared with the head. Magnetic interaction, due to clustering of grains, is also identi¢ed by the measurements. Analysis of magnetic extracts by transmission electron microscopy identi¢es the presence of uniquely ultra¢ne (10 nm) and unidimensional grains of ferrimagnetic material, unequivocally distinct from any possible extraneous magnetite sources, such as ingested soil. Hence, this provides ¢rm evidence for biogenic formation of this magnetic material by these two termite species. Such ultra¢ne grains would be superparamagnetic, i.e. incapable of carrying a permanent magnetic moment, unless they were sited in clusters of interacting grains, when some remanence-carrying abilityöand hence magnetotaxisöwould be possible.

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“…By using a very sensitive magnetometer, SQUID (Superconducting Quantum Interference Device), magnetic materials carrying remanent magnetization were measured on migratory birds (Presti & Pettigrew 1980) and homing pigeons (Walcott, Gould & Kirschvink 1979, Presti & Pettigrew 1980, as well as on bees (Gould, Kirschvink & Deffeyes 1978), monarch butterfly (Jones & MacFadden 1982), dolphin (Zoeger, Dunn & Fuller 1980), and woodmice (Mather & Baker 1981). Presti & Pettigrew (1980) have described appreciable magnetic remanences in both the head and the neck of the migratory birds and the pigeons.…”

Section: Introductionmentioning

confidence: 99%

Magnetic Remanences in Migratory Birds

Ueda

Kusunoki

Katô

et al. 1982

Journal of the Yamashina Institute for Ornithology

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In connection with indications of the magnetic field detection in migratory birds, the measurements of magnetic remanences were carried out in both the migratory birds (Rustig Bunting and Reed Bunting) and the non-migratory birds (Siberian Meadow Bunting and Tree Sparrow) by means of SQUID magnetometer. Regardless of whether the species was migratory or not, neither heads nor neck musculatures indicated any presence of intrinsic magnetic materials related to the sensory mechanisms. The natural remanence and the induced remanence were of the orders of 10-8-10-7 e.m.u. and of 10-7-10-6 e.m.u. respectively. The magnetic sensor of birds for a compass reception is discussed.

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Pigeons Have Magnets

Abstract: Research on pigeon homing suggests that magnetic field information is used for orientation. The ability of pigeons to sense magnetic fields may be associated with a small, unilateral structure between the brain and the skull which contains magnetic in what appears to be single domains.

Cited by 270 publications

References 15 publications

Sudden motility reversal indicates sensing of magnetic field gradients in Magnetospirillum magneticum AMB-1 strain

Sudden motility reversal indicates sensing of magnetic field gradients in Magnetospirillum magneticum AMB-1 strain

Magnetite biomineralization in termites

Magnetic Remanences in Migratory Birds

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