electric eel

This eel-like fish, 2 to 2.5 meters long, is brown/green with a white/yellow to orange belly. It does not have caudal, dorsal, or pectoral fins. The anal fin is long.

Although the species has gills, it also breathes through its mouth. The mouth is highly vascularized, facilitating gas exchange. To breathe in poorly oxygenated areas, the electric eel surfaces to "gulp" air. This characteristic allows the electric eel to move on land and inhabit low-oxygen dead river branches.

The electric eel emits electric discharges thanks to modified muscles at the back of its body. It is also capable of analyzing an electric field through receptors located under its head.

The modified muscle cells, also called electrocytes, generate a current that can exceed 700 volts at 2 amperes. This discharge is sufficient to stun a large prey.

This ability also serves for electrolocation: the electric eel can navigate in murky waters thanks to the electric field it emits.

The electric eel is mainly nocturnal. Like most electric fish, it creates an electric field around itself that allows it to determine the nature of objects around it. A animal or object will modify this electric field by its charge, giving the electric eel information about its environment.

Electrophorus electricus is an active hunter. When prey is detected, the animal approaches and emits an electric discharge that stuns the prey. The prey is then ingested by the electric eel. Adults are piscivores and juveniles feed on invertebrates.

We count 3 types of possible discharges in this fish: a low voltage impulse for electrolocation, high voltage impulses for hunting, and high voltage and high frequency impulses for prey capture and defense.

It is not uncommon for individuals to leap out of the water to attack prey or defend themselves. Kenneth Catania, from Vanderbilt University, observed that this action intensifies the voltage.

The dry season, between September and December, marks the start of the breeding season. The male creates a nest covered with mucus along the banks by digging into the mud. The female then deposits around ten thousand eggs which the male fertilizes. The male then guards the eggs and larvae until the first mid-January rains arrive. The approximately 10 cm long juveniles are then dispersed by the now stronger currents.

The first hatching larvae exhibit cannibalistic behavior towards the eggs and other larvae that hatch later. On average, only about a thousand larvae develop until the rainy season. Electric discharges can be produced as early as 1.5 centimeters.