The electric eel can generate an electric charge of over 800V, raising the question of why this charge does not harm the electric eel itself.
The electric eel (Electrophorus electricus) is the largest species in the knifefish family, renowned for its unique ability to generate electricity. Originating from South America, it primarily inhabits the Amazon and Orinoco river basins. This species is currently classified as endangered in the Red List of threatened species.
First, we need to understand the mechanism by which the electric eel generates electricity. Essentially, almost all animals have the ability to produce electric signals. This process occurs whenever a nerve or muscle cell is activated, generating a small amount of electricity.
This electricity is crucial for performing important functions, from regulating the heart rate to enabling movement in animals. You can think of each cell in an animal’s body as a battery generating energy.
An experiment measuring the electric current of the electric eel.
The key difference with electric eels is that each of their cells acts like a battery with a charge of nearly 100V. The electric eel produces large amounts of electricity thanks to a specialized nervous system capable of synchronizing the activity of disc-shaped electric-producing cells organized in a “power plant” running along their elongated bodies.
The eel’s nervous system accomplishes this through a command nucleus that decides when the electric organs will activate. When commanded, a complex network of nerves ensures that thousands of cells are activated simultaneously, regardless of their distance from the command center.
Upon receiving a control signal, the nerve endings release a small amount of acetylcholine, a neurotransmitter. This creates a temporary pathway with low resistance connecting the inside and outside of one side of the cell. Consequently, each cell operates like a battery, with the activated side carrying a negative charge and the opposite side carrying a positive charge. When these 100-volt batteries are activated, the entire system can generate an electric current of up to 860 volts, about three times higher than the voltage of an average electrical outlet in Vietnam.
What do the victims of the electric eel experience?
The terrifying voltage of up to 860 volts generated by the electric eel can paralyze large animals and even lead to their death. This has created a notorious reputation for the electric eel.
The most common victims are unfortunate individuals who come too close to the electric eel. In some cases, other electric eels may also suffer from the electrical discharge.
Generally, every animal possesses a “biological electrical circuit.” Initially, the electric current from the electric eel disrupts this biological circuit and causes dysfunction. For example, triggering abnormal muscle contractions can lead to paralysis, allowing the eel to either consume its prey or escape.
In worse cases, prolonged paralysis can directly lead to the death of the electric eel’s victim.
How does the electric eel avoid harming itself?
The activation of the “power plant” within the electric eel simultaneously generates a short-term electric current running along its body. If the electric eel comes into contact with air, the current can reach up to 1 ampere, making its body equivalent to a 500-volt battery. However, when submerged in water, the electric eel generates a higher voltage, but the water diffuses the current, reducing the voltage level.
Moreover, the severity of an electric shock depends on the amount and duration of the current passing through any specific area of the body. To compare, the body of an eel is approximately the same size as an adult male’s arm. To induce a muscle spasm in an arm, a current of 200 milliamperes must flow into that arm for 50 milliseconds.
An electric eel is not in much danger because its current only runs through its body for 2 milliseconds before dissipating externally. Additionally, due to the eel’s resistance being greater than that of water, a significant portion of the current dissipates into the water through its slimy skin. This reduces the harmful effects of the electric current on vital organs such as the brain or heart of the electric eel.
Furthermore, when activating the current, the electric eel instinctively employs techniques to minimize self-harm. The curling movements of the electric eel help to distance its sensitive internal organs from the electric flow.
When discharging electricity, the eel will instinctively position its brain and vital organs towards the front of its body. This area is outside the direct path of the electric current and is surrounded by a thick layer of fat that enhances insulation.
All of these factors enable the electric eel to avoid harm from its own electric shocks.
