INTRODUCTION: Several mammalian species spontaneously align their body axis with respect to the Earth's magnetic field (MF) lines in diverse behavioral contexts. Magnetic alignment is a suitable paradigm to scan for the occurrence of magnetosensitivity across animal taxa with the heuristic potential to contribute to the understanding of the mechanism of magnetoreception and identify further functions of magnetosensation apart from navigation. With this in mind we searched for signs of magnetic alignment in dogs. We measured the direction of the body axis in 70 dogs of 37 breeds during defecation (1,893 observations) and urination (5,582 observations) over a two-year period. After complete sampling, we sorted the data according to the geomagnetic conditions prevailing during the respective sampling periods. Relative declination and intensity changes of the MF during the respective dog walks were calculated from daily magnetograms. Directional preferences of dogs under different MF conditions were analyzed and tested by means of circular statistics. RESULTS: Dogs preferred to excrete with the body being aligned along the North-South axis under calm MF conditions. This directional behavior was abolished under unstable MF. The best predictor of the behavioral switch was the rate of change in declination, i.e., polar orientation of the MF. CONCLUSIONS: It is for the first time that (a) magnetic sensitivity was proved in dogs, (b) a measurable, predictable behavioral reaction upon natural MF fluctuations could be unambiguously proven in a mammal, and (c) high sensitivity to small changes in polarity, rather than in intensity, of MF was identified as biologically meaningful. Our findings open new horizons in magnetoreception research. Since the MF is calm in only about 20% of the daylight period, our findings might provide an explanation why many magnetoreception experiments were hardly replicable and why directional values of records in diverse observations are frequently compromised by scatter.

Department of Game Management and Wildlife Biology Faculty of Forestry and Wood Sciences Czech University of Life Sciences 16521 Praha 6 Czech Republic

Department of General Zoology Faculty of Biology University of Duisburg Essen 45117 Essen Germany

See more in PubMed

Begall S, Červený J, Neef J, Vojtěch O, Burda H. Magnetic alignment in grazing and resting cattle and deer. Proc Natl Acad Sci USA. 2008;105:13451–13455. doi: 10.1073/pnas.0803650105. PubMed DOI PMC

Burda H, Begall S, Červený J, Neef J, Němec P. Extremely low-frequency electromagnetic fields disrupt magnetic alignment of ruminants. Proc Natl Acad Sci USA. 2009;106:5708–5713. doi: 10.1073/pnas.0811194106. PubMed DOI PMC

Begall S, Burda H, Červený J, Gerter O, Neef-Weisse J, Němec P. Further support for the alignment of cattle along magnetic field lines. Reply to Hert et al. J Comp Physiol A. 2011;197:1127–1133. doi: 10.1007/s00359-011-0674-1. PubMed DOI PMC

Slabý P, Tomanová K, Vácha M. Cattle on pastures do align along the North–South axis, but the alignment depends on herd density. J Comp Physiol A. 2013. DOI 10.1007/s00359-013-0827-5. PubMed

Červený J, Begall S, Koubek P, Nováková P, Burda H. Directional preference may enhance hunting accuracy in foraging foxes. Biol Lett. 2011;7:355–357. doi: 10.1098/rsbl.2010.1145. PubMed DOI PMC

Begall S, Malkemper EP, Červený J, Němec P, Burda H. Magnetic alignment in mammals and other animals. Mammal Biol. 2013;78:10–20.

Hart V, Kušta T, Němec P, Bláhová V, Ježek M, Nováková P, Begall S, Červený J, Hanzal V, Malkemper EP, Štípek K, Vole C, Burda H. Magnetic alignment in carps: evidence from the Czech Christmas fish market. PLoS One. 2012;7:e51100. doi: 10.1371/journal.pone.0051100. PubMed DOI PMC

Hart V, Malkemper EP, Kušta T, Begall S, Nováková P, Hanzal V, Pleskač L, Ježek M, Policht R, Husinec V, Červený J, Burda H. Directional compass preference for landing in water birds. Frontiers Zool. 2013;10:38. doi: 10.1186/1742-9994-10-38. PubMed DOI PMC

Vanderstraeten J, Burda H. Does magnetoreception mediate biological effects of power-frequency magnetic fields? Sci. Total Environm (STOTEN) 2012;417–418:299–304. PubMed

Harry W. The homing of a dog. Science. 1922;56:339. PubMed

Phillips R, Mech L. Homing behavior of a red fox. J Mammal. 1970;51:621. doi: 10.2307/1378406. DOI

Henshaw RE, Stephenson RO. Homing in the gray wolf (Canis lupus) J Mammal. 1974;55:234–237. doi: 10.2307/1379281. DOI

Danner DA, Fisher AR. Evidence of homing by a coyote (Canis latrans) J Mammal. 1977;58:244–245.

Kusak J, Skrbinšek AM, Huber D. Home ranges, movements, and activity of wolves (Canis lupus) in the Dalmatian part of Dinarids, Croatia. Europ J Wildlife Res. 2005;51:254–262. doi: 10.1007/s10344-005-0111-2. DOI

Bensky MK, Gosling SD, Sinn DL. The world from a dog’s point of view: a review and synthesis of dog cognition research. Adv Study Anim Behav. 2013;45:209–406.

Bähr A, Wolf E. Domestic animal models for biomedical research. Repr Domest Anim. 2012;47:59–71. PubMed

Burda H, Marhold S, Westenberger T, Wiltschko W, Wiltschko R. Magnetic compass orientation in the subterranean rodent Cryptomys hottentotus (Bathyergidae, Rodentia) Experientia. 1990;46:528–530. doi: 10.1007/BF01954256. PubMed DOI

Agnetta B, Hare B, Tomasello M. Cues to food location that domestic dogs (Canis familiaris) of different ages do and do not use. Anim Cogn. 2000;3:107–112. doi: 10.1007/s100710000070. DOI

Miklósi Á, Polgárdi R, Topál J, Csányi V. Use of experimenter-given cues in dogs. Anim Cogn. 1998;1:113–121. doi: 10.1007/s100710050016. PubMed DOI

Virányi Z, Topál J, Gácsi M, Miklósi Á, Csányi V. Dogs respond appropriately to cues of humans’ attentional focus. Behav Proc. 2004;66:161–172. doi: 10.1016/j.beproc.2004.01.012. PubMed DOI

Courtillot V, Le Mouel JL. Time variations of the Earth’s magnetic field: from daily to secular. Ann Rev Earth Planet Sci. 1988;16:389–476. doi: 10.1146/annurev.ea.16.050188.002133. DOI

Liboff AR. Why are Living Things Sensitive to Weak Magnetic Fields? Electromagn Biol Med. 2013. pp. 1–5. doi:10.3109/15368378.2013.809579. PubMed

Southern WE. Influence of disturbances in the earth’s magnetic field on Ring-billed Gull orientation. Condor. 1972;74:102–105.

Keeton WT, Larkin TS, Windsor DM. Normal fluctuations in the earth’s magnetic field influence pigeon orientation. J Comp Physiol. 1974;95:95–103. doi: 10.1007/BF00610108. DOI

Moore FR. Geomagnetic disturbance and the orientation of nocturnally migrating birds. Science. 1977;196:682–684. doi: 10.1126/science.854743. PubMed DOI

Martin H, Lindauer M. Der Einfluss des Erdmagnetfeldes auf die Schwereorientierung der Honigbiene (Apis mellifera) J Comp Physiol. 1977;122:145–187. doi: 10.1007/BF00611888. DOI

Vanselow KH, Ricklefs K. Are solar activity and sperm whale Physeter macrocephalus strandings around the North Sea related? J Sea Res. 2005;53:319–327. doi: 10.1016/j.seares.2004.07.006. DOI

Dimitrova S, Stoilova I, Cholakov I. Influence of local geomagnetic storms on arterial blood pressure. Bioelectromagnetics. 2004;25:408–414. doi: 10.1002/bem.20009. PubMed DOI

Berk M, Dodd S, Henry M. Do ambient electromagnetic fields affect behaviour? A demonstration of the relationship between geomagnetic storm activity and suicide. Bioelectromagnetics. 2006;27:151–155. doi: 10.1002/bem.20190. PubMed DOI

Ritz T, Thalau P, Phillips JB, Wiltschko R, Wiltschko W. Resonance effects indicate a radical-pair mechanism for avian magnetic compass. Nature. 2004;429:177–180. doi: 10.1038/nature02534. PubMed DOI

Winklhofer M, Kirschvink JL. A quantitative assessment of torque-transducer models for magnetoreception. J Roy Soc Interface. 2010;7:273–289. doi: 10.1098/rsif.2009.0435.focus. PubMed DOI PMC

Phillips JB, Muheim R, Jorge PE. A behavioral perspective on the biophysics of the light-dependent magnetic compass: a link between directional and spatial perception? J exp Biol. 2010;213:3247–3255. doi: 10.1242/jeb.020792. PubMed DOI

Turning preference in dogs: North attracts while south repels

Magnetic alignment enhances homing efficiency of hunting dogs

Ectosymbionts alter spontaneous responses to the Earth's magnetic field in a crustacean

Dogs can be trained to find a bar magnet

Directional preference in dogs: Laterality and "pull of the north"

Magnetoreception in the wood mouse (Apodemus sylvaticus): influence of weak frequency-modulated radio frequency fields

Spontaneous expression of magnetic compass orientation in an epigeic rodent: the bank vole, Clethrionomys glareolus