Magnetic alignment in grazing and resting cattle and deer
Magnetic alignment in grazing and resting cattle and deer
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DOI：
10.1073/pnas.0803650105
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发表时间：
2008-09-09
影响因子：
11.1
通讯作者：
Burda, Hynek
中科院分区：
文献类型：
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作者：
Begall, Sabine;Cerveny, Jaroslav;Burda, Hynek
我们通过简单、非侵入性的方法（分析卫星图像、实地观察和测量雪中的“鹿床”）证明，全球范围内的家牛（308 个牧场中的 n = 8,510 头）以及放牧和休息的红鹿和狍子（241 个地点中的 n = 2,974 头）的身体轴大致沿南北方向排列。对狍子的直接观察表明，动物在吃草或休息时会将头朝北。令人惊讶的是，这种普遍存在的现象似乎并没有被牧民、牧场主或猎人注意到。由于风和光条件可以被排除在确定身体轴方向的公分母之外，因此磁对准是最简洁的解释。为了验证牛的身体轴沿着地球磁场的磁力线定向的假设，我们分析了来自高磁偏角地区的牛的身体方向。在这里，磁北比地理北更能预测。这项研究基于统计上足够的样本量揭示了大型哺乳动物的磁排列。我们的研究结果为一般磁感受研究开辟了视野，并对应用行为学（畜牧业、动物福利）具有潜在意义。他们向神经科学家和生物物理学家提出挑战，要求他们解释其直接机制。
We demonstrate by means of simple, noninvasive methods (analysis of satellite images, field observations, and measuring "deer beds" in snow) that domestic cattle (n = 8,510 in 308 pastures) across the globe, and grazing and resting red and roe deer (n = 2,974 at 241 localities), align their body axes in roughly a north-south direction. Direct observations of roe deer revealed that animals orient their heads northward when grazing or resting. Amazingly, this ubiquitous phenomenon does not seem to have been noticed by herdsmen, ranchers, or hunters. Because wind and light conditions could be excluded as a common denominator determining the body axis orientation, magnetic alignment is the most parsimonious explanation. To test the hypothesis that cattle orient their body axes along the field lines of the Earth's magnetic field, we analyzed the body orientation of cattle from localities with high magnetic declination. Here, magnetic north was a better predictor than geographic north. This study reveals the magnetic alignment in large mammals based on statistically sufficient sample sizes. Our findings open horizons for the study of magnetoreception in general and are of potential significance for applied ethology (husbandry, animal welfare). They challenge neuroscientists and biophysics to explain the proximate mechanisms.