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In all the world, there are more than two hundred different species of what are known as “ animals electric ”, that is to say, those that use electricity to stun their prey or defend against predators. All of them live in aquatic environments because they need water as an element conductor of electricity.

The oldest record of fish electric of which we have news are the representations of the cat fish of the Nile in the murals of some egyptian tombs, dating back to the 2.750 in. of C.

however, it can be said that these animals did not enter by the great door of the science, until in 1766 the naturalist Swedish Carlos Linnaeus first described the electric eel ( Electrophorus electricus ) of the Amazon river.

Electricity animal and biomimicry

Long before electricity was understood, we had many practical knowledge obtained from the experience. Thus, for example, the egyptians used a stripe marine electrical to treat epilepsy, in the pre-columbian America used the electric eel to mitigate the drop and in ancient China the electric catfish is recommended to alleviate the drooping of the eyelid –ptosis – and the facial paralysis.

John Walsh, John Hunter and Henry Cavendish were the first scientists who discovered that the electricity of the torpedo fish came from two organs located on both sides of the body and which, moreover, were formed by columns of cells stacked.

This would be the scientific basis that inspired Alessandro Volta (1745-1827) to design the first battery of volts of constant current, the first stack of the history of science.

Basically it was a column pretty high on the that were stacked up –hence the name – circles of copper and zinc separated by a wet cloth. In short, Volta did an apology biomimicry (from Greek bio-, life, and mimesis-imitate) to manufacture the battery electric. Later, I would discover that if the water was replaced by certain saline solutions the voltage increased sharply.

Electrocitos: specialized cells

The ability to generate power is due to a few specialized cells called electrocitos. It was a few hundred million years ago –when the dinosaurs were the kings of our planet – when a group of muscle cells evolved to this cell line.

When the electrocitos receive a chemical signal triggers the opening of certain selective channel which causes the entry of sodium ions and the outflow of potassium ions. This ion exchange amplifies the voltage on the membrane, causing the opening of more channels and giving rise to an electrical signal that travels through the cell.

The electrical discharges of the fish are located, specifically, two pairs of electric organ that they have in the cranial cavity and that will work like a battery. One of them is called the organ of Sachs –in honor of the naturalist Carl Sachs – and produces discharges of low voltage, not to exceed 10 volts.

on the contrary, the other body -of Hut – starting downloads of greater intensity and that they may last for a minute, that they come to kill their prey. In the case of the Electrophorus voltai have come to record up to 680 volts, a figure able to electrocute a bull.

Taking a look back, not andaríamos very ill-advised to afirmásemos Volta was inspired by the organ of Sachs, while Harold P Brown –the inventor of the electric chair – did the same in the body of the Hut.

Pedro Gargantilla is a internist in the Hospital of El Escorial (Madrid), and author of several popular books

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