Several groups of mammals use the Earth's magnetic field for orientation, but their magnetosensory organ remains unknown. The Ansell's mole-rat (Fukomys anselli, Bathyergidae, Rodentia) is a microphthalmic subterranean rodent with innate magnetic orientation behaviour. Previous studies on this species proposed that its magnetoreceptors are located in the eye. To test this hypothesis, we assessed magnetic orientation in mole-rats after the surgical removal of their eyes compared to untreated controls. Initially, we demonstrate that this enucleation does not lead to changes in routine behaviours, including locomotion, feeding and socializing. We then studied magnetic compass orientation by employing a well-established nest-building assay under four magnetic field alignments. In line with previous studies, control animals exhibited a significant preference to build nests in magnetic southeast. By contrast, enucleated mole-rats built nests in random magnetic orientations, suggesting an impairment of their magnetic sense. The results provide robust support for the hypothesis that mole-rats perceive magnetic fields with their minute eyes, probably relying on magnetite-based receptors in the cornea.

中文翻译：

---

眼睛对于哺乳动物的磁感受至关重要


几类哺乳动物利用地球磁场进行定向，但它们的磁感应器官仍然未知。安塞尔鼹鼠（Fukomys anselli、Bathyergidae、Rodentia）是一种具有先天磁定向行为的小眼球地下啮齿动物。先前对该物种的研究表明，其磁感受器位于眼睛中。为了检验这一假设，我们评估了鼹鼠在手术摘除眼睛后与未经治疗的对照组相比的磁定向。最初，我们证明这种摘除不会导致日常行为的改变，包括运动、进食和社交。然后，我们通过在四种磁场排列下采用成熟的筑巢测定法来研究磁罗盘方向。与之前的研究一致，对照动物表现出在地磁东南方筑巢的显着偏好。相比之下，去核的鼹鼠以随机的磁方向筑巢，这表明它们的磁感受损。这些结果为鼹鼠用微小的眼睛感知磁场的假设提供了强有力的支持，这可能依赖于角膜中基于磁铁矿的受体。