In the 17th century, the Italian biologist Stefano Lorenzini discovered that sharks have a set of pores in their heads, which became known as the Ampullae of Lorenzini. However, it wasn’t until the 20th century that we understood their function: these pores are used to measure electric signals.
The primary function of the ampullae of Lorenzini is to detect minute electrical fields in the water. All living organisms produce electrical fields through muscle contractions and nerve impulses, and these signals are particularly pronounced in the aquatic environment, where they can propagate through the salty water. Sharks and rays utilize this system to detect the electrical fields generated by the muscle contractions of potential prey, even when hidden under sand or mud.
Besides hunting, the ampullae of Lorenzini assist in navigation. The Earth’s magnetic field induces electrical fields in the ocean as seawater moves through it, creating a kind of natural electromagnetic map. By detecting these fields, sharks and rays can effectively navigate vast distances in the open ocean, a phenomenon known as electro-navigation.
We humans typically talk about the world in light of our five senses, but that is a very anthropocentric way of looking at the world. The Ampullae of Lorenzini is an example of a sense that we cannot perceive, but it is experienced every day by some animals and serves as another reminder of how incredible wildlife is.Go deeper: The Discovery of the Shark's Electric Sense - The American Scientist
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