Dogs are sensitive to small variations of the Earth’s magnetic field

Abstract

IntroductionSeveral 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.ResultsDogs 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.ConclusionsIt 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.

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

“…Consequently, although there is insufficient information to determine if the observed preference in wood mice is innate or learned, it appears likely that at least some component of the response is innate. Although the adaptive significance of spontaneous magnetic alignment remains an open question 8 44 45 46 , the widespread occurrence in epigeic mammals makes this response ideal for initial studies of the mechanism(s) of magnetoreception.…”

A geomagnetic declination compass for horizontal orientation in fruit flies

“…Therefore, it is reasonable to consider that there has been no convincing evidence for the magnetic compass that underlies the observed flies' horizontal orientations. Second, recent studies that showed magnetosensitive body alignment in two animal species (Bazalova et al ; Hart et al ) supported the possibility that animals can exhibit magnetoreceptive behavior by sensing changes in declination without detection of the direction of geographic north. Cockroaches could sense repeated changes in magnetic direction caused by the shift of the horizontal component of the GMF; they showed significant correlated body alignment within an interval of a few minutes without any geographic directional cue in the testing arena (Bazalova et al ).…”

“…The daily variation of declination reaches a few tenths of a degree even in the absence of solar disturbance (Finlay et al 2010;Thébault et al 2015). Although the scale of variation appeared to be very small, magnetosensitive animals such as dogs appeared to be able to detect such minute variation as described above (Hart et al 2013). If this also somehow happened in the fruit flies, they were probably able to use both the inclination and declination compasses at the same time.…”

“…Cockroaches could sense repeated changes in magnetic direction caused by the shift of the horizontal component of the GMF; they showed significant correlated body alignment within an interval of a few minutes without any geographic directional cue in the testing arena (Bazalova et al ). In addition, the north–south body alignment of domesticated dogs during excretion in open fields was specifically dependent on the rate of change in the declination, but not the absolute value of declination or total‐, vertical‐, horizontal‐intensity of the GMF (Hart et al ). Thus, very subtle change in declination of the order of 0.0007°/min was enough to disturb the significant body alignment, highlighting the high sensitivity of these animals to declination change.…”

Some Tonal and Rhythmical Sequences in the Vocal Language of Dogs as Significant Earthquake Precursors

“…Malkemper and others, proved the magnetic sensitivity in dogs. The conclusion of their paper states [41]: "magnetic sensitivity was proved in dogs, a measurable, predictable behavioural reaction upon natural MF fluctuations could be unambiguously proven in a mammal, and high sensitivity to small changes in polarity, rather than in intensity, of MF was identified as biologically meaningful". As we can see in Table 13, the magnetic anomalies of both declination and intensity of the FM occur suddenly and frighten the dogs, who do not see the "enemy" as when they see an intruder in their territory, but perceive the magnetic change with their magneto-sensitive receptors and are disoriented, just as the birds are also disorientated, and which in these moments can "make mistakes" in the direction of flight and go slamming into plants.…”