Data from: The geomagnetic environment in which sea turtle eggs incubate affects subsequent magnetic navigation behavior of hatchlings

Loggerhead sea turtle hatchlings (Caretta caretta) use regional magnetic fields as open-ocean navigational markers during trans-oceanic migrations. Little is known, however, about the ontogeny of this behavior. As a first step toward investigating whether the magnetic environment in which hatchlings develop affects subsequent magnetic orientation behavior, eggs deposited by nesting female loggerheads were permitted to develop in situ either in the natural ambient magnetic field or in a magnetic field distorted by magnets placed around the nest. In orientation experiments, hatchlings that developed in the normal ambient field oriented approximately south when exposed to a field that exists near the northern coast of Portugal, a direction consistent with their migratory route in the northeastern Atlantic. By contrast, hatchlings that developed in a distorted magnetic field had orientation indistinguishable from random when tested in the same north Portugal field. No differences existed between the two groups in orientation assays involving responses to orbital movements of waves or sea-finding, neither of which involves magnetic field perception. These findings demonstrate for the first time that the magnetic environment present during early development can influence the magnetic orientation behavior of a neonatal migratory animal.蠵龟（Loggerhead sea turtle, Caretta caretta）幼崽在跨洋迁徙过程中，会借助区域磁场作为远海航行的定位标记。然而，学界对该行为的个体发育机制仍知之甚少。为探究幼崽发育所处的磁环境是否会影响其后续的磁定向行为，研究人员将筑巢雌龟所产的卵原位安置于两种磁场环境中发育：一组处于自然环境磁场，另一组则通过在巢穴周围放置磁铁，使磁场发生畸变。在磁定向实验中，发育于正常自然磁场的幼崽，在暴露于葡萄牙北海岸附近的磁场环境时，其定向方向大致为南向，这一方向与其在东北大西洋的迁徙路线相符。与之形成鲜明对比的是，发育于畸变磁场中的幼崽，在接受同一葡萄牙北部磁场测试时，其定向表现与随机选择无显著差异。两组幼崽在针对波浪轨道运动或海洋定位的定向测试中均未表现出差异——这两类测试均不涉及磁场感知。本研究的发现首次证实，早期发育阶段所处的磁环境，能够影响迁徙类新生动物的磁定向行为。