Eels are elongated fish found in diverse aquatic environments, ranging from freshwater rivers to the depths of the ocean. Their snake-like appearance often sparks curiosity about whether these creatures pose a threat to humans. While many eel species are harmless, some possess unique defense mechanisms that warrant caution.
Common Eel Species and Their Risks
Several types of eels can cause harm, primarily through bites or electric shocks. Moray eels, found in tropical and subtropical marine waters, are recognized for their powerful jaws and sharp teeth. Conger eels, which can grow to considerable sizes, also pose a biting risk due to their strength and dental structure. Electric eels, a type of knifefish native to South American freshwater systems, are known for their ability to generate powerful electrical discharges.
The Threat of Eel Bites
Moray eels are not inherently aggressive but will bite defensively if provoked or their hiding places are disturbed. These eels possess sharp teeth that curve backward, making it difficult for prey, or an inadvertently placed hand, to escape once gripped. Morays also have a second set of jaws, known as pharyngeal jaws, which help them secure and pull prey deeper into their throats.
A moray eel bite can result in lacerations, puncture wounds, and significant bleeding. The injury’s severity often depends on the eel’s size, with larger species capable of inflicting more extensive tissue damage, potentially leading to the loss of a digit. Beyond immediate physical trauma, a concern with moray eel bites is the risk of infection. Moray eels have bacteria in their mouths, including species like Vibrio and Pseudomonas, which can lead to serious infections if the wound is not promptly and thoroughly cleaned. Their mucus and slime also contain toxins.
The Power of Electric Eels
Electric eels are characterized by their remarkable ability to generate electricity. These South American fish possess specialized organs, making up about 80% of their body mass, that contain modified muscle cells called electrocytes. When triggered, these electrocytes act like biological batteries, creating an electrical impulse by rapidly transferring ions across cell membranes.
Electric eels produce varying strengths of electric impulses; weaker ones are used for navigation and locating prey, while stronger discharges are employed for defense and stunning prey. Some species, like Electrophorus voltai, can generate up to 860 volts, while others range from 400 to 650 volts, with a current around 1 amp. While a single shock is rarely fatal to a healthy adult, it can cause muscle spasms and temporary paralysis. The primary danger to humans often comes from indirect effects, such as being incapacitated and drowning, especially in shallow water. Multiple shocks can also lead to respiratory or heart failure, particularly for individuals with pre-existing heart conditions.
Minimizing Encounters and Risks
To reduce the risk of harmful encounters with eels, observe them from a safe distance and avoid disturbing their natural habitats. Never reach into rocky crevices or other potential hiding places where eels might be residing, as this is a common cause of defensive bites from moray eels. Refrain from attempting to touch or feed any eel, as this can habituate them to human presence and increase the likelihood of an aggressive response.
When in aquatic environments known to harbor eels, particularly electric eels, exercise caution in murky or shallow waters. If an encounter occurs, remain calm and slowly move away. In the event of a bite or electric shock, seek medical attention promptly. For bites, thoroughly clean the wound with soap and water to prevent infection. Medical assessment is important for any injury to ensure proper treatment, including potential antibiotics or stitches, and to check for broken teeth left in the wound.