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Quantum Compass of Migratory Birds

 

 

mutual cancellation of the EED and electronic exchange coupling, as previously suggested. Babcock and

Kattnig (2020) then demonstrated that this limitation may be overcome by extending the conventional

model to include a third, non-reacting radical. Tey predicted that hyperfne efects could work in con­

cert with three-radical dipolar interactions to tailor a superior magnetic response, thereby providing a

new principle for magnetosensitivity with applications for sensing, navigation, and the assessment of

biological magnetic feld efects (Babcock and Kattnig, 2020).

In recent years, it is known that electromagnetic phenomena can be observed with earthquakes and

that electromagnetic noise is generated in a wide frequency band as one of the earthquake precursors

(reviewed by Conti et al., 2021). It is not clear whether the magnetic sensor of the animal is involved in

the anomalous phenomenon, but the possibility cannot be ruled out because abnormal animal behaviors

and physiological conditions have been observed before the large earthquake (Ikeya et al., 1996; Yokoi

et al., 2003; Garstang, 2009; Li et al., 2009; Yanai et al., 2012; Hayakawa, 2013; Whitehead and Ulusoy,

2013; Fidani et al., 2014; Yamauchi et al., 2014, 2017; Orihara et al., 2019). However, informative criti­

cal reviews on abnormal animal behaviors for the earthquake precursor have been published (Woith

et al., 2018; Conti et al., 2021). Woith et al. (2018) reviewed 180 publications regarding abnormal animal

behavior before earthquakes and analyze and discuss them with respect to (1) magnitude–distance rela­

tions, (2) foreshock activity, and (3) the quality and length of the published observations. More than 700

records of claimed animal precursors related to 160 earthquakes are reviewed with unusual behavior

of more than 130 species. Te precursor time ranges from months to seconds prior to the earthquakes,

and the distances from a few to hundreds of kilometers. However, only 14-time series were published,

whereas all other records are single observations. Te time series are ofen short (the longest is 1 year), or

only small excerpts of the full data set are shown. Te probability density of foreshocks and the occur­

rence of animal precursors are strikingly similar, suggesting that at least parts of the reported animal

precursors are in fact related to foreshocks. Another major difculty for a systematic and statistical

analysis is the high diversity of data, which are ofen only anecdotal and retrospective. Tus, the review

of Woith et al. (2018) clearly demonstrated strong weaknesses or even defcits in many of the published

reports on possible abnormal animal behavior. Conti et al. (2021) reported that animal magnetic sensi­

tivity that could be even greater than the instrumental sensitivity of measurements made in various test

campaigns to study earthquake precursors would cut across so many diferent species that they do not

share other important sensory characteristics. Conti et al. (2021) proposed that systematic monitoring

campaigns with continuous bio-logging of animal collectives, including movements and physiological

parameters, could yield valuable insights on this topic.

If the model can be constructed by imitating the high-sensitivity magnetic sensor of migratory birds,

it can be expected that new innovations can be made in predicting and measuring environmental

changes accompanied by magnetic anomalies including earthquakes (Oka, 2015). Basic research related

to magnetic sensing of migratory birds has not been clarifed yet and has been the subject of debate in

recent years, especially in the feld of physics and biophysics, and it is considered to have high potential

as innovative and applied research. In this way, it is expected that an environment-friendly lifestyle and

system will be created by learning from the environment and life on Earth, as well as by utilizing the

knowledge in various research felds.

References

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magnetic feld delays Arabidopsis thaliana fowering time through downregulation of fowering-

related genes. Bioelectromagnetics 39(5):361–374.

Agliassa, C., Narayana, R., Christie, J.M., and Mafei, M.E. 2018b. Geomagnetic feld impacts on crypto­

chrome and phytochrome signaling. J Photochem Photobiol B Biol 185:32–40.

Ahmad, M., and Cashmore, A.R. 1993. HY4 gene of A. thaliana encodes a protein with characteristics of

a blue-light photoreceptor. Nature 366(6451):162–166.