Further support for the alignment of cattle along magnetic field lines: reply to Hert et al.
Hert et al. (J Comp Physiol A, 2011) challenged one part of the study by Begall et al. (PNAS 105:13451–13455, 2008) claiming that they could not replicate the finding of preferential magnetic alignment of cattle recorded in aerial images of Google Earth. However, Hert and co-authors used a different statistical approach and applied the statistics on a sample partly unsuitable to examine magnetic alignment. About 50% of their data represent noise (resolution of the images is too poor to enable unambiguous measurement of the direction of body axes, pastures are on slopes, near settlements or high voltage power-lines, etc.). Moreover, the authors have selected for their analysis only ~ 40% of cattle that were present on the pastures analyzed. Here, we reanalyze all usable data and show that cattle significantly align their body axes in North–South direction on pastures analyzed by Hert and co-authors. This finding thus supports our previous study. In addition, we show by using aerial Google Earth images with good resolution, that the magnetic alignment is more pronounced in resting than in standing cattle.
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- Begall S, Cerveny J, Neef J, Vojtech O, Burda H (2008) Magnetic alignment in grazing and resting cattle and deer. PNAS 105:13451–13455 CrossRef
- Burda H, Begall S, Cerveny J, Neef J, Nemec P (2009) Extremely low-frequency electromagnetic fields disrupt magnetic alignment of ruminants. PNAS 106:5708–5713 CrossRef
- Hert J, Jelinek L, Pekarek L, Pavlicek A (2011) No alignment of cattle along geomagnetic field lines found. J Comp Physiol A 197:677–682
- Mardia KV, Jupp PE (2000) Statistics of directional data. Wiley, Chicester, p 429
- Šárová R, Špinka M, Panamá JLA, Šimeček P (2010) Graded leadership by dominant animals in a herd of female beef cattle on pasture. Animal Behav 79:1037–1045
- Further support for the alignment of cattle along magnetic field lines: reply to Hert et al.
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Journal of Comparative Physiology A
Volume 197, Issue 12 , pp 1127-1133
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- Magnetic alignment
- Resting behavior
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- Author Affiliations
- 1. Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, 45117, Essen, Germany
- 2. Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, 16521, Praha 6, Czech Republic
- 3. Department of Zoology, Faculty of Science, Charles University in Prague, 12844, Praha 2, Czech Republic