An electric eel can slam prey with 860 volts, enough to knock a grown adult off their feet

The electric eel is not really an eel at all, but a long, air-breathing knifefish of South America’s rivers, and it is one of the few animals capable of turning its own body into a battery. For two centuries scientists believed there was a single species, capable of powerful but roughly comparable shocks. Then field measurements revealed a specimen that discharged 860 volts, the highest voltage ever recorded from a living animal, and rewrote part of the story.

A body wired to generate electricity

An electric eel devotes most of its considerable length, which can exceed six feet, to specialized electric organs made of thousands of modified muscle cells called electrocytes. Stacked in series like the cells of a battery, each electrocyte produces only a small voltage, but when the animal fires them in unison the tiny charges add up into a single powerful pulse. The eel maintains three electric organs that let it produce both weak discharges, used for navigation and communication in murky water, and the high-voltage bursts it uses to hunt and defend itself. Because the animal lives in oxygen-poor waters and must surface to breathe air, it has evolved this electrical system alongside an unusual respiratory one, making it one of the more physiologically distinctive fish in the world.

The discovery of a record-setting species

For roughly 250 years, the electric eel was classified as a single species, Electrophorus electricus. That changed in 2019, when a team led by researchers associated with the Smithsonian Institution examined more than a hundred specimens collected across the vast region of northern South America they call Greater Amazonia. Analyzing genetics, anatomy and habitat, the scientists concluded that there were actually three distinct species. As detailed by the Smithsonian, one of the newly described species, named Electrophorus voltai after Alessandro Volta, the Italian inventor of the electric battery, lives in the highland waters of the Brazilian Shield and proved to be the most powerful of the three.

Measuring 860 volts in the field

The headline number came from a direct measurement. Using a voltmeter on live specimens, the researchers recorded a discharge of 860 volts from an Electrophorus voltai, far above the roughly 650 volts previously documented for the classic electric eel. That reading, described in reporting from Cornell University, stands as the highest voltage known from any animal. Scientists have proposed that the fish living in the clearer, more mineral-poor highland waters may have evolved stronger discharges to compensate for water that conducts electricity less efficiently, though the reasons remain an active question. What is clear is that the discovery upended the assumption that all electric eels are electrically alike.

What 860 volts actually does

A discharge in that range is genuinely dangerous, and the comparison to knocking a person off their feet is grounded in real accounts. A large eel’s high-voltage pulse can cause a strong involuntary muscle contraction in a human who touches it, and the naturalist who first recorded the highest voltage, biologist Carlos David de Santana, has described taking shocks during fieldwork. For the eel’s usual prey of small fish, the effect is decisive: the pulse overrides the victim’s own nervous system, causing its muscles to seize so the eel can seize it. Research has shown that electric eels can even curl their bodies to concentrate the field, and that they sometimes leap from the water to press their electric organ directly against a threat, delivering the charge more effectively through the air-and-body path than through the surrounding water. The danger to a person lies less in a single jolt being lethal than in the shock triggering a fall or, in deep water, incapacitation.

Voltage, current and the limits of the comparison

It is worth being precise about what the numbers mean. Voltage measures the electrical pressure driving a current, but the harm an electric shock does depends on the current that actually flows, how long it lasts and the path it takes through the body. An electric eel’s discharge is high in voltage but brief, delivered in rapid pulses, which is part of why encounters are usually painful and disorienting rather than fatal to a healthy adult. Reports gathered by institutions including the University of Central Florida, where de Santana has worked, underscore that the 860-volt figure is a record of peak electrical pressure produced by the animal, not a measure of a guaranteed knockout. The honest framing is that a full-strength shock from a large electric eel is powerful enough to cause a painful, potentially dangerous jolt and to knock a person down, especially in water, while the precise outcome depends on the circumstances of the encounter.

A living battery still full of questions

The electric eel has fascinated science since the earliest studies of electricity, and Volta’s invention of the battery was itself partly inspired by animals that generate their own current. Nearly two centuries after those experiments, the discovery of a species capable of an 860-volt discharge shows how much remains unknown about even a famous animal. Researchers are still working out why some populations evolved stronger shocks, how the fish avoids electrocuting itself, and what its specialized cells might teach engineers about generating and storing power. For an animal long treated as a single well-understood curiosity, the electric eel keeps proving that it has surprises left, wired into the length of its remarkable body.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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