While on the hunt, a supreme awareness of the surroundings can pay off large dividends for an individual. One species that takes advantage of their surroundings is the shark. In Life, a shark quickly reacts to the movements of a school of anchovies by sensing the electrical signals given off by their collective movement, giving the shark an advantage while hunting. Sharks have a “sixth sense” called electroreception, which enables them to sense weak electrical stimuli conducted through ocean water via electrosensory receptors on the surface of their skin . This enables them to hunt precisely underwater, sensing the weak voltage generated by the muscle contractions of their prey . These tiny electrical signals can be picked up by the sharks due to salty ocean water being such a great medium for conduction. Although the exact developmental origin of electroreceptors is still not fully understood , electroreception can be seen in a variety of other species, including bees and dolphins. Research has delved into the possibility of the evolution of unique head morphology for the enhancement of these electrosensory capabilities , but these studies have proven inconclusive so far. Thus the search continues for the origin of this unique characteristic, and the phenomenon behind its mysterious evolutionary path.
by Gracy Trinoskey-Rice and Jason McCartney
Life, Season 1, Episode 4, Fish, starting at approximately 42:08
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