We’re now learning that turtles have not one but two different ways of sensing the Earth’s magnetic field. “The turtles can sense the magnetic ‘flavor’ of a location… Precisely how they do this is still a mystery, but two distinct mechanisms might be involved,”says Henry Gee, a senior editor at Nature.
“Our results demonstrate that an animal can learn the natural magnetic signatures of geographical areas, thus corroborating a foundational premise of goal navigation with magnetic maps.”
See also the accompanying briefing: “Sea turtles use magnetic ‘map’ and ‘compass’ to navigate the ocean.”
https://microwavenews.com/papers/two-mechanisms-magnetoreception-turtles