Learned magnetic map cues and two mechanisms of magnetoreception in turtles

Abstract

Overview

Growing evidence supports that migratory animals use the Earth's magnetic field for navigation, serving both as a directional compass and a geographical map. While animals are known to use magnetic compasses, the concept of a learned magnetic map has not been fully explored.

Findings

The study demonstrates that loggerhead turtles (Caretta caretta) can learn magnetic signatures associated with specific geographic areas. Juvenile turtles, when repeatedly exposed to magnetic fields representing specific oceanic locations during feeding, learned to differentiate between these and other magnetic fields. This ability may contribute to foraging site fidelity in turtles. Notably, their learning was not influenced by conditions that disrupt chemical-based magnetoreception, suggesting a different underlying mechanism for the magnetic map compared to the magnetic compass, which was affected.

Conclusion

The research indicates that two distinct mechanisms of magnetoreception are utilized by sea turtles: one for the magnetic map and another for the magnetic compass. This distinction adds a significant layer of understanding to animal navigation theories.