Function and processes underlying magnetic sensing in young loggerhead sea turtles

Animals across diverse taxa possess the ability to sense and use the magnetic field of Earth to aid their navigation and orientation. This globally ubiquitous cue may be leveraged as both a “compass” that determines direction and a “map” that assesses global position. Despite the widespread nature of this sensory system, many fundamental questions about the physical bases, function, and development of magnetoreception remain unresolved. My dissertation research examines these questions through a series of behavioral experiments with young loggerhead sea turtles (Caretta caretta), a species known to use their magnetic sense throughout their life history for various navigational tasks. Using an assay that required their magnetic “map”, I investigated the anatomical location of magnetic sensory receptors and the different functional sensitivities of the magnetic map sense, compared to the magnetic compass. I then studied the development and nature of a suite of magnetic responses displayed by hatchling turtles in another assay, and the vulnerability of these responses to disturbances from solar activity. This research advances our understanding of both the remarkable magnetoreception abilities displayed by sea turtles and broader principles of magnetoreception across diverse species.