Electroreception: Sharks Are Hardwired for the Hunt

posted: 04/11/12
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Depending on whom you ask, it can be difficult to get a consensus on how many senses sharks — and people, for that matter — actually have. But regardless of how you want to classify typical sensations like smell or vision, there's one sense that puts sharks into the lead: electroreception.

Electroreception happens in sharks' ampullae of Lorenzini, which are part of a special set of organs called lateral line sensory organs. It's pretty much what it sounds like: Sharks have the ability to sense electricity. This might not seem like a big deal, but it's actually a huge edge — living things generate electrical fields, and salt water is an excellent conductor. Pores filled with conductive jelly pick up electrical signals and transmit them to the shark's brain.

Some sharks seem to use these sensors most advantageously for methodical, close-range hunting. Hammerheads, for example, sweep their huge heads back and forth over sandy seafloors to find buried prey. Others appear to use their electroreception to keep track of prey just before a strike — as soon as electrolyte-filled blood starts filling the water, escape is almost impossible. Some sharks may also use electroreception over greater lengths, possibly in tandem with the Earth's magnetic field, to assist their long-distance navigation.

Sharks also have other special senses that come from their lateral line sensory organs. These include the ability to sense water displacement, vibration, movement and pressure changes. With all that in mind, it's probably no surprise that the total number of shark senses is open to debate.

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