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How do electric eels make electricity?

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Quick answer

Electric eels generate electricity using stacks of specialised cells called electrocytes. When triggered by a nerve signal, these cells allow ions to flow, creating a voltage. Thousands of electrocytes stacked in series add up to a powerful discharge, reaching up to 600 volts, used for hunting and defense.

Electric eels generate electricity using specialised cells called electrocytes, which are stacked in series like batteries. When a signal from the brain triggers them, ions flow across each cell's membrane, adding up to a powerful discharge.

Step by step

  1. The electric eel's brain sends a signal through its nervous system to the electric organs.
  2. The signal reaches the electrocytes, which are flat, disc-like cells stacked in long columns.
  3. Ion channels open on only the nerve-facing side of each electrocyte, so sodium ions rush in there, creating about 0.15 volts across the cell.
  4. Because the cells are stacked in series, their voltages add up, similar to batteries in a flashlight.
  5. When the eel discharges, all the electrocytes fire at once, producing a strong current that flows through the water.
  6. The current stuns or kills prey by interfering with their nerve signals, making them easy to capture.

Key things to understand

  1. Electric eels have three electric organs: the main organ, Hunter's organ, and Sachs' organ, each with different functions.
  2. The main organ produces the strong, brief shocks used for hunting and defense.
  3. Electrocytes are modified muscle cells that cannot contract; instead, a nerve signal opens ion channels on one face to make a voltage.
  4. Each electrocyte generates about 0.15 volts, but thousands stacked in series can produce up to 600 volts.
  5. The shock is released in short pulses, and the eel can control the strength and duration.

Labelled diagram

  1. Brain signal

    The brain sends a command through nerves to the electric organs.

  2. Electrocytes

    Specialised cells in the electric organ respond to the signal.

  3. Ion channels

    Channels open on one face only, so ions flow unevenly and create a voltage.

  4. Series stack

    Thousands of cells stacked in series add up their voltages.

  5. Discharge

    All cells fire together, releasing a powerful current into the water.

How an electric eel generates a shock

Real-world examples

  • Electric eels in South America's Amazon and Orinoco basins can discharge around 600 volts, enough to jolt a large animal such as a horse.
  • In 2019, a new species of electric eel, Electrophorus voltai, was found to produce 860 volts, the highest known for any animal.
  • Electric eels are not true eels but belong to the knifefish family, and they use electricity to navigate murky waters.
  • Researchers study electric eels to inspire new battery designs and medical devices that use electrical stimulation.

Common mistake

✗ Myth: Electric eels can generate electricity continuously.

✓ Fact: Electric eels only discharge in short pulses, and they need time to recharge their electrocytes between shocks. Continuous discharge would quickly exhaust them.

People also ask

How do electric eels produce electricity?
Electric eels produce electricity using specialised cells called electrocytes, which are stacked in series. When a nerve signal triggers them, ions flow across each cell's membrane, creating a voltage. The combined voltage of thousands of cells can reach up to 600 volts, which the eel uses to stun prey or defend itself.
What is the voltage of an electric eel?
Electric eels can produce discharges ranging from about 10 volts for navigation to as high as 600 volts for stunning prey. In 2019, a newly discovered species, Electrophorus voltai, was recorded producing 860 volts, the highest known for any animal.
Are electric eels dangerous to humans?
Electric eels can be dangerous to humans. A strong shock can cause muscle spasms, numbness, and even temporary paralysis. While deaths are rare, the shock can lead to drowning if a person is in the water. It's best to avoid contact and seek medical attention if shocked.
Can electric eels shock themselves?
Rarely. Fatty insulating tissue around vital organs, and a current path that runs out through the water, protect the eel from most of its own discharge, though how complete this protection is remains under study.
How do electric eels avoid shocking themselves when hunting?
They curl their body so that the current flows through the prey and not through their own vital organs. The electric organs are also positioned so that the discharge path avoids the heart and brain.
Do electric eels use electricity for communication?
Yes, they emit low-voltage pulses to communicate with other eels, especially during mating season. These signals are too weak to stun prey but can be detected by other eels.
What happens if you touch an electric eel?
You could receive a painful shock that may cause muscle spasms, numbness, or even temporary paralysis. In rare cases, the shock can be dangerous, so it's best to avoid contact and seek medical help if shocked.

Part of the guide: Nature & Earth: Living Things and Rocks →