Electric eels are unique freshwater fish native to South America, known for their remarkable ability to generate powerful electrical discharges. While their name suggests a close relation to true eels, they are actually a type of knifefish, more closely related to species like catfish and carp. This adaptation enables them to navigate, hunt, and defend themselves.
The Shocking Truth: How Much Voltage?
The voltage an electric eel can produce varies depending on factors such as its size, maturity, and specific species. In 2019, research identified two additional species: Electrophorus voltai and Electrophorus varii. Electrophorus electricus can generate up to 600 volts. Electrophorus varii produces discharges ranging from 151 to 572 volts. The most potent of the three, Electrophorus voltai, can deliver shocks up to 860 volts.
The Biological Battery: How Electricity is Generated
Electric eels possess specialized electric organs that comprise about 80% of their body mass. These organs, known as the main organ, Hunter’s organ, and Sachs’ organ, generate electrical power from modified muscle cells called electrocytes. These disc-shaped cells are stacked in columns, functioning much like cells in a battery, each creating a small potential difference, around 0.15 volts. When the eel’s nervous system activates these cells, thousands of electrocytes discharge simultaneously, combining their voltages to produce a strong electric current. The main and Hunter’s organs are responsible for high-voltage discharges, while Sachs’ organ produces lower voltage pulses.
More Than Just a Jolt: Uses of Electric Discharges
Electric eels utilize their electrical discharges for a variety of functions. High-voltage shocks, generated by the main and Hunter’s organs, are used to stun prey and deter predators. These powerful pulses can lead to involuntary muscle contractions in prey, effectively paralyzing them. If prey is concealed, the eel might emit brief, high-voltage pulses to induce a twitch, which creates water movement that reveals the prey’s location.
Lower-voltage pulses, produced by Sachs’ organ, are used for navigation, communication, and sensing their environment. These weaker discharges, typically around 10 volts, create an electric field around the eel. By detecting distortions in this field, the eel can identify objects or other organisms in murky waters. Additionally, these low-voltage signals facilitate communication between eels, with varying frequencies potentially conveying information about sex or reproductive readiness.
Safety and Impact
An electric eel’s shock can be painful and hazardous to humans, although a single discharge is rarely lethal. Shocks are known to cause intense pain, muscle spasms, and temporary paralysis; despite the high voltage, the amperage is relatively low, which is why a single shock is unlikely to be fatal for a healthy adult. However, repeated shocks can lead to more severe outcomes such as respiratory or heart failure, especially for those with pre-existing heart conditions, the elderly, or very young. A significant risk also involves secondary injuries, such as drowning, if a person is incapacitated by a shock while in water. Electric eels can even emerge from the water to deliver a more concentrated shock to perceived threats.