Eels are elongated, fish-like creatures found across diverse aquatic environments, including freshwater, brackish, and marine habitats. With over 800 known species, they exhibit a wide range of appearances and behaviors. While some eels can bite, serious injuries or fatalities are exceedingly rare and typically occur as defensive reactions. The widespread belief that all eels are inherently aggressive or electric is a misconception; most species pose little threat to humans.
Electric Eels: The Shocking Truth
Electric eels, belonging to the genus Electrophorus, are freshwater fish native to South America, found in the Amazon and Orinoco river basins. Despite their name, they are not “true” eels in the biological sense but are a type of knifefish more closely related to catfish and carp. These unique fish have evolved specialized organs, including the main organ, Hunter’s organ, and Sach’s organ, which constitute about 80% of their body mass and enable them to generate powerful electric shocks.
Electric eels can produce discharges ranging from 480 to 860 volts, with some species like Electrophorus voltai generating the highest voltages. They use these shocks for hunting prey and for self-defense. When an electric eel delivers a high-voltage shock, it can result in painful muscle contractions, temporary paralysis, and disorientation in humans. While a single shock is rarely fatal, multiple shocks can lead to respiratory failure or heart problems. The primary danger often stems from incapacitation, which can lead to drowning, especially in shallow water.
Moray Eels: Caution for Divers
Moray eels (family Muraenidae) are true eels found in tropical and subtropical marine environments, often hiding in crevices and coral reefs. There are approximately 200 species of moray eels, which vary in size and appearance. They possess powerful jaws with sharp, backward-curving teeth designed to grip prey, and some species also have a second set of pharyngeal jaws to pull food into their throats.
Moray eels are not venomous, but their bites can be severe due to their strength and the potential for deep lacerations. The mucus that covers their skin can contain toxins in some species, and while the exact toxicity of their bites is considered low, secondary infections are a significant concern due to bacteria in their mouths. Moray eels typically bite when they feel threatened, are provoked, or if divers mistakenly offer them food. It is important to seek medical attention for a moray eel bite to prevent infection and address potential bleeding and swelling.
The Majority of Eels: Generally Harmless
The vast majority of eel species, such as conger eels, garden eels, and freshwater eels, are not considered dangerous to humans. These eels are generally shy and prefer to avoid human interaction. If a bite occurs, it is typically a defensive action resulting in a minor, superficial wound. Fatal encounters with eels are rare and almost always involve specific circumstances or particular species like the electric eel or severe moray eel bites.