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Scientists have discovered that loggerhead sea turtles can learn and remember the unique magnetic signatures of different geographic regions. The breakthrough provides the first empirical evidence supporting the idea that turtles use learned magnetic cues to navigate long distances with remarkable accuracy. The study also shows that turtles possess two distinct magnetic senses, furthering our understanding of how migratory animals perceive and use the Earth's magnetic field.
Loggerhead turtles and magnetic navigation
Researchers at the University of North Carolina at Chapel Hill have provided the first concrete evidence that loggerhead sea turtles can learn and remember the unique magnetic signatures of different geographic regions. The discovery sheds new light on how turtles and other migratory animals travel vast distances to reach feeding and breeding grounds. The study, published February 12 in the journal Nature Communications, Nature magazine, also suggests that sea turtles have two distinct magnetic senses, each playing a different role in detecting the Earth's magnetic field.
Loggerhead turtles are known for their amazing long-distance migrations, relying on an internal magnetic map to determine their location based on fluctuations in the Earth's magnetic field. While scientists have long suspected that turtles can also learn and recognize specific magnetic fields associated with important locations, there has been no direct evidence to support this until now.
Breakthrough in animal navigation research
"Our study is the first to investigate whether a migrating animal can learn to recognize the magnetic signatures of different geographic areas," said Kayla Goforth, the study's first author. "Researchers have suspected for decades that animals can learn magnetic signatures, but this is the first empirical demonstration of such an ability, so it fills an important gap in our knowledge."
Through controlled experiments, the research team demonstrated that terrapins can indeed learn and remember the magnetic fields of the places where they obtain food. This ability suggests that the turtles use learned magnetic information to navigate back to their foraging sites, helping to explain their remarkable navigational accuracy over long distances. More broadly, these findings could apply to a wide range of migratory animals that rely on magnetic cues for navigation.
“The ability to distinguish between the magnetic fields of different geographic areas likely explains how many animals — not just sea turtles — can travel long distances to specific locations,” said Ken Lohmann, a professor of biology at UNC-Chapel Hill.
Two different magnetic sensations
The study also delves into the underlying mechanisms of magnetic sensing. The results show that the turtles' magnetic map and magnetic compass senses rely on different ways of detecting magnetic fields, suggesting that these animals have two distinct magnetic senses. This discovery provides a significant advance in the broader scientific understanding of how animals perceive and use the Earth's magnetic field.
In addition to the implications for science, the study holds promise for conservation efforts and human technological advancement. Understanding how turtles detect and interpret magnetic fields could help conservationists mitigate disruptions caused by man-made structures, such as power lines and offshore wind farms, that can interfere with natural magnetic signals. In addition, the findings of this study could contribute to the development of new navigation technologies inspired by nature.
Unraveling the mysteries of turtle navigation
“We’ve known for 20 years that sea turtles have magnetic maps, and now that we’ve shown that they can explore new places, we’ve learned how maps can be created and modified,” said Katherine Lohmann, a professor of biology at UNC-Chapel Hill. “It’s amazing that sea turtles have access to a wealth of invisible information that they use to navigate in ways that we can’t even imagine.”
The interdisciplinary nature of the research highlights the importance of collaboration across disciplines. Notably, the specialized antenna system created for this study closely resembles the technology used for individual studies, demonstrating the broad application of electromagnetic principles.
"It's remarkable that the antenna system we built for the turtle study is almost identical to the antenna system we've been working on to search for dark matter," said Reiko Henning, a professor in the Department of Physics and Astronomy at UNC-Chapel Hill. "This is a great example of the broad application of the laws of electromagnetism."
Future directions of research
The researchers plan to continue studying the turtles' ability to learn, their sensitivity to magnetic fields, and how they integrate the information they learn into real-world navigation. The findings open the door to exciting new research and highlight the vital role of interdisciplinary collaboration in advancing scientific knowledge.
