The loggerhead sea turtle is a species of oceanic turtle distributed throughout the world.
It is a marine reptile, belonging to the family Cheloniidae.
The average loggerhead measures around 90 cm in carapace length when fully grown
Sea turtles are known for their long migrations and ability to return to specific feeding sites.
Scientists believe they use Earth's magnetic field as both a map and a compass.
Experiment Setup: Researchers housed juvenile turtles in tanks and recreated magnetic signatures of different geographical locations.
The turtles were only fed in one of the magnetic field environments.
"Turtle Dance": When placed in the magnetic field associated with food, the turtles exhibited a "turtle dance," a behavior indicating anticipation of feeding. This suggests they learned to associate a specific magnetic signature with food.
Magnetic Map: This "turtle dance" behavior provides strong evidence that turtles can distinguish between different magnetic fields, essentially creating an internal "magnetic map" of their environment.
Two Separate Senses: The research indicates that this "magnetic map" sense is distinct from the magnetic "compass" sense turtles use for orientation.
This means they have two separate mechanisms for using magnetic fields in navigation.
Mechanism of Magnetic Map Sense: The study found that the "magnetic map" sense is not affected by radiofrequency oscillating magnetic fields, unlike the magnetic "compass" sense.
This suggests that the magnetic map sense doesn't rely on the same chemical mechanism (radical-pair-based magnetoreception) as the magnetic compass.
Implications: The findings reveal that turtles have a sophisticated understanding of magnetic fields, using them in complex ways for navigation, including learning and remembering the magnetic signatures of specific locations.
The discovery of two distinct magnetic senses further emphasizes the complexity of their navigational abilities.
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