Electric Eel
Electrophorus electricus Our Wild World
https://adlayasanimals.wordpress.com/2015/09/13/electric-eel-electrophorus-electricus/
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Electric eels are not true eels at all. Instead, they are members of the knifefish family and inhabit the murky rivers, streams, lakes, and flooded forests of the Amazon and Orinoco basins. Scientists currently recognize three species: Electrophorus electricus, Electrophorus voltai, and Electrophorus varii. Although electric eels have been known to science for centuries, researchers only recognized these three distinct species in 2019.
Among them, Electrophorus electricus is particularly notable for its size, reaching lengths of up to eight feet (Smithsonian's National Zoo and Conservation Biology Institute). These elongated fish are among the largest freshwater predators in South America and occupy a variety of habitats, from slow-moving rivers to seasonally flooded forests.
As their name suggests, electric eels are capable of producing powerful electric discharges. Their electricity comes from specialized cells called electrocytes, which are stacked together like thousands of tiny batteries. When activated simultaneously, these cells generate a powerful electric field. Electrophorus voltai can produce shocks of up to 860 volts, making it the animal with the highest known voltage output on Earth (FAPESP, 2019). This remarkable ability inspired the work of Alessandro Volta, whose studies of electricity eventually led to the invention of the first electric battery (Chetan-Welsh).
Electric eels use electricity in several different ways. Weak electric pulses help them navigate through muddy water, communicate with other eels, and locate prey hidden in the darkness. Stronger discharges are used to stun prey and defend against predators (Smithsonian's National Zoo and Conservation Biology Institute). Scientists have discovered that electric eels can even manipulate the nervous systems of nearby animals, causing prey to involuntarily twitch and reveal their location.
Life in the Amazon's murky waters presents unique challenges. Visibility is often limited, and oxygen levels can be extremely low. To survive in these conditions, electric eels have evolved to breathe air and must regularly surface to gulp oxygen. In fact, most of the oxygen they use comes from the atmosphere rather than from the water. Their bodies are also equipped with highly sensitive electroreceptors and mechanoreceptors that allow them to detect movement and electrical signals produced by other animals.
Although electric eels are generally solitary hunters, scientists have made the surprising discovery that they occasionally hunt cooperatively. Researchers observed groups of more than one hundred electric eels herding schools of fish into dense clusters before launching synchronized electric attacks that stunned dozens of fish at once (Moutinho, 2021). This behavior was the first known example of social predation in electric eels and suggests that these fish may be more behaviorally complex than previously believed.
Electric eels possess another remarkable adaptation: despite their long, eel-like appearance, most of their vital organs are crowded into the front portion of their bodies, while the majority of their length is devoted to the organs that generate electricity. This unusual anatomy allows them to maximize their electric output while maintaining the flexibility needed to navigate flooded forests and tangled vegetation.
From their extraordinary electrical abilities and air-breathing adaptations to their surprising social behaviors, electric eels are among the most fascinating animals of the Amazon basin. Scientists continue to study these remarkable fish, and future discoveries may reveal even more about how they survive and thrive in one of the world's most diverse ecosystems.
References:
Electric Eel Electrophorus electricus. Smithsonian’s National Zoo and Conservation Biology Institute
https://nationalzoo.si.edu/animals/electric-eel
FAPESP. (September 10, 2019) A new species of electric eel produces the highest voltage discharge of any known animal PHYS.ORG
https://phys.org/news/2019-09-species-electric-eel-highest-voltage.html
Chetan-Welsh, Holly. How electric eels work? Natural History Museum
https://www.nhm.ac.uk/discover/how-do-electric-eels-work.html
Moutinho, Sofia. (January 14, 2021) Shocking discovery: Electric eels hunt in packs in Amazon rivers Social predation spotted for the first time among these animals Science