Dogs are sensitive to
small variations of the Earth’s magnetic field.
Vlastimil Hart, Petra Nováková, Erich Pascal
Malkemper, Sabine Begall, Vladimír Hanzal, Miloš Ježek1,Tomáš Kušta, Veronika
Němcová, Jana Adámková, Kateřina Benediktová, Jaroslav Červený and Hynek Burda.
ABSTRACT
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.
Keywords: Magnetoreception,
Magnetosensitivity, Magnetic field, Magnetic storm, Magnetic alignment, Dog,
Canid, Mammal
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