Sharks have a special electric sense that enables them to home in on small electric signals generated by prey. But the special electroreceptors in their skin also appear to be important in the long trans-oceanic migrations made by some species.
The receptors develop small electrical currents in response to temperature gradients, and this may help those species that follow warm-water currents. They are also sensitive enough to measure the voltage gradients (or ‘electrical signals’) produced by the movement of oceanic water through the Earth’s magnetic field, as well as those generated by the shark’s movements through that field. It’s thought that this allows sharks to navigate as if they had their own magnetic compass.
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