Meeting Abstract
Foraging site fidelity describes a pattern of behavior in which animals return to the same foraging area repeatedly, in some cases after migrating to distant sites. Juvenile sea turtles of several species exhibit this behavior, with turtles reliably returning to specific foraging grounds following seasonal migrations and experimental displacements. Turtles are known to have a magnetic map sense that exploits variation in Earth’s magnetic field to identify and travel to distant sites. Because of this variation, different geographic locations have slightly different magnetic fields, thus, most foraging areas have a unique “magnetic signature”. In principle, turtles might learn to navigate to a specific foraging area by learning the magnetic signature of that site. To investigate this possibility, we studied whether turtles are capable of learning to associate a magnetic signature with food. Captive loggerhead turtles (Caretta caretta) approximately three months of age, were assigned to one of two experimental groups and conditioned to a unique magnetic field. Each group was exposed to two different magnetic signatures, on a daily alternating schedule, over the course of two months. Turtles spent equivalent amounts of time in the two magnetic signatures, but only received food in one of them. In post-conditioning trials conducted in the absence of food, turtles exhibited higher levels of food-seeking behavior when exposed to the magnetic field in which they had previously been fed, but not when exposed to the other magnetic field. These results provide the first direct evidence that sea turtles can learn to associate a magnetic field with food, a process that may underlie the development of foraging site fidelity.
