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Electric eel facts for kids

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Electric eel
Electric-eel.jpg
Electrophorus electricus at the New England Aquarium
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Gymnotiformes
Family: Gymnotidae
Gill, 1872
Genus: Electrophorus
Gill, 1864
Type species
Gymnotus electricus
Linnaeus, 1766
Species

see text

Electric eels are a type of fish from South America famous for their amazing ability to create electricity. They can produce powerful shocks of up to 860 volts to stun their prey and defend themselves. Studying these fish even helped scientists invent the first electric battery back in 1800.

Despite their name, electric eels are not actually eels. They are a type of knifefish and are more closely related to catfish. For over 200 years, scientists thought there was only one species of electric eel. But in 2019, they discovered there are actually three different species!

These unique fish are active at night and have poor eyesight. They use a special sense called electrolocation to "see" the world around them with electricity. They are also one of the few fish that need to come to the surface to breathe air.

Not a True Eel

When the electric eel was first described by the famous scientist Carl Linnaeus in 1766, he named it Gymnotus electricus. He thought it was related to other knifefish. Later, in 1864, another scientist named Theodore Gill gave it its own genus, Electrophorus. The name comes from Greek words meaning 'electricity bearer'.

For a very long time, everyone believed there was only one species of electric eel. However, in 2019, a team of scientists studied the eel's DNA and physical features. They found enough differences to split them into three separate species. This was a huge discovery in the world of science!

The Three Species of Electric Eel

The three known species of electric eel look very similar, but they live in different parts of South America and have unique features.

Anguilles électriques 3 espèces Nature 10 sept 2019 C. David de Santana et al
Differences between the three species of electric eel: E. electricus, E. voltai, and E. varii.
Bodies (top to bottom) of E. electricus, E. voltai, and E. varii

Habitat and Hunting Habits

Electric eels live in the freshwaters of South America, like the Amazon and Orinoco river basins. They prefer muddy bottoms in rivers and swamps, often in shady areas. Because they can breathe air, they can survive in water that doesn't have much oxygen.

Electric eels are nocturnal, meaning they are most active at night. They are skilled predators that mainly eat other fish. They use their low-voltage electric sense to find prey in the dark. Once they locate a meal, they release a powerful, high-voltage shock to stun it before eating it.

Interestingly, some electric eels, like E. voltai, have been seen hunting in groups. They work together to herd smaller fish into a tight ball and then shock them all at once.

Carte du nord de l'Amérique du sud avec répartition de spécimens de 3 espèces d'anguilles électriques electrophorus
Map showing where the three species of Electrophorus live in South America: E. electricus (1, red); E. voltai (2, blue); E. varii (3, yellow).

Biology

Body and Anatomy

Electrophorus electricus - squelette MNHN (cropped)
Electric eel skeleton. The long backbone is at the top, with the bony rays of the long fin below it.

Electric eels have long, snake-like bodies that can grow up to 2 meters (6.6 feet) long. Their skin is smooth and thick, usually dark brown or black with a yellow or orange belly. They don't have any scales.

Most of their important organs, like the heart and stomach, are packed into the front 20% of their body. The other 80% is filled with their special electric organs. They swim by moving their long anal fin in a wave-like motion.

One of the most unusual things about electric eels is that they are obligate air-breathers. This means they must come to the surface about every two minutes to gulp air. They use special tissues in their mouth to absorb oxygen. This allows them to live in muddy, low-oxygen water where other fish might not survive.

How the Shock Works

Electrophorus electricus showing lateral line pits
The pits on the eel's head are part of its lateral line system. They help it sense movement and electricity in the water.

The electric eel's shock comes from three pairs of special organs: the main organ, Hunter's organ, and Sachs' organ. These organs are made of thousands of modified muscle cells called electrocytes.

Think of each electrocyte as a tiny biological battery. When the eel wants to shock something, its brain sends a signal. This signal causes thousands of these "batteries" to discharge all at once. Because the electrocytes are stacked in long rows, their power adds up to create a massive voltage. An eel can have around 6,000 electrocytes in a single row!

Biotechnology, systems biology, artificial cells (5940428301)
Anatomy of an electric eel's electric organ. The organs are made of stacks of cells called electrocytes. Each cell acts like a tiny battery.

Low and High Voltage

Electric eels can produce two different kinds of shocks:

  • Low-Voltage Pulses: The Sachs' organ produces weak pulses of about 10 volts. The eel uses this like a radar system for electrolocation. It helps them navigate and find prey in dark or murky water.
  • High-Voltage Shocks: The main organ and Hunter's organ work together to create powerful shocks of 600 volts or more. These are used to stun prey or as a defense against predators. An eel can release hundreds of these high-voltage pulses in just a few seconds.

To make its shock even more powerful, an eel will often curl its body around its prey. This makes the electric current pass through the victim more effectively. They have even been seen leaping out of the water to shock threats on land!

Impedance matching in electric fishes
This diagram shows why electric eels need a high voltage. Freshwater is not a good conductor of electricity, so the eel needs a lot of power to deliver a strong shock.

Life Cycle

Electric eels breed during the dry season. The male builds a nest out of his own saliva for the female to lay her eggs in. A female can lay over 1,000 eggs.

After the eggs hatch, the young larvae will eat any leftover eggs for their first meal. The male parent is very protective and guards the nest and the young for several months.

Electric eels grow throughout their entire lives. They can live for a long time, with some in aquariums living for over 20 years.

Human Encounters and Discoveries

Humans have been fascinated and frightened by electric eels for centuries. Early explorers in South America wrote stories about these mysterious fish that could numb a person's body with a touch.

Humboldt's Famous Story

In 1800, the famous explorer Alexander von Humboldt wrote about a dramatic method used to catch electric eels. Local fishermen would drive a group of horses into a pond full of eels. The eels would attack the horses, leaping out of the water to deliver powerful shocks. After discharging their electricity many times, the tired eels were easy to catch with small harpoons.

Inspiring Science

The electric eel played a big role in the history of science.

  • The First Battery: Studies of the eel's electricity in the late 1700s helped inspire Alessandro Volta to invent the first electric battery.
  • Proving it's Electricity: In the 1830s, scientist Michael Faraday conducted many experiments on an electric eel. He proved that the shock it produced was the same as the electricity that created sparks and ran through wires.

Today, scientists are still studying electric eels. They hope to learn from the eel's efficient electric organs to design new types of power sources, perhaps for medical implants or other small devices.

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See also

Kids robot.svg In Spanish: Anguilas eléctricas para niños

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