Homing Turtles and Animal Magnetism

Abstract

This chapter studies the magnetic sense of animals. A magnetic sense is widespread in nature and allows a variety of animals to detect the Earth’s geomagnetic field, and to use this for orientation and navigation over short and longer distances. The chapter looks at how animals use magnetic cues and magnetic maps, which is illustrated by the much-studied sea turtles. Turtles inherit a magnetic map that allows them to calculate their position in the ocean and adjust their orientation appropriately so they can travel towards a specific goal. However, it is not only turtles that achieve remarkable feats of navigation. A number of fish species also travel great distances during different phases of their lives, often returning to natal spawning grounds to breed later on. Meanwhile, over twenty bird species have been clearly demonstrated to use magnetic information as a compass and to respond to different components of the magnetic field. The key evidence for how the avian magnetic sense works is based on a magnetite process.