The electric eels (Electrophorus electricus in scientific terms) are one of the most feared freshwater animals, since they have the incredible ability to generate electric shock through their body´s cells, which are overcoming stronger animals and even humans.
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What are Electric Eels?
First of all we must mention that electric eels are fish that belong to the Gymnotidae family, which is a family of species that lives mainly in fresh water, usually in Central America and some South American Countries. These feared creatures have the capacity to emit electrical discharges of up to 850 volts, since they have specialized cells that make it possible. According to the aforementioned and as their name indicates, the electric eels stands out among other species mainly for their awesome ability to emit electrical discharges being this its most prominent aspect. They employ such skills to hunt their prey, to defend against their predators and to communicate with their peers.
Electric eels are not real eels. The classifications have varied putting them in their own family, Electrophoridae. Today they are considered generally related to Gymnotus, known as «knife fish», «mouse fish» or «morenitas»; like these, they are voracious predators.
The Electric Eels´ Anatomy
The electric eels are characterized by being long snake-like fish, which can generate electricity (they are not true eels). They can grow up to almost 8 feet (2.5 m) long and reach 20 kilograms of weight. Their skin is greenish gray, their head is flattened and their mouth is large, with a row of conical teeth in each jaw. Most of their internal organs are in their front part while the rest of the body contains the organs that produce electricity (modified muscles). The scales that cover their body are tiny, their eyes are small, and as they age, their vision decreases while the amperage of their electric discharge increases. As for their gills, they are modified into «lung-like» organs, so they must emerge occasionally to swallow air.
The Electric Eels´ Discharge
Their skill to generate electric shock relies on their nervous system, and especially to a series of cells that produce electricity housed in an electrical organ. The nervous system emits an order for this organ to be put into operation and a group of nerves ensures that the cells are activated at the same time.
Each of these cells has a negative charge of just under 100 millivolts on its outside. The signal sent by the nervous system releases a neurotransmitter called acetylcholine. This substance is the main electricity conductor of this species, and allows their electrons circulate to any required place. The cell is like a battery, with a negative charge, and another with a positive charge, and each cell is joined to the others side by side, causing the current to flow through the eel´s body. Then the water increases the voltage making it higher, helped by the presence of salt and other minerals.
As in the case of other animals, eels use their skills mainly to create electric fields and detect their prey when they distort such fields. If someone gets in their way, the eel will notice because something will not be good with the electrical energy of the environment generated by it.
In humans, the shock produced by electric eels is very similar to that of a paralyzing gun, causing brief and painful paralysis due to over-activation of the muscles. Kenneth Catania, researcher of the electric eel and scientist at Vanderbilt University, recently developed a device to measure the discharges of electric eels and, to prove it, he used his own arm as bait! The electric current released by the eel reached a maximum of 40-50 milliamps. That is more than enough to cause a person or animal considerable pain, but not enough to really hurt him.
It is not necessarily a shock that can kill a person, and attacks on people are rare, but a meeting could lead to death. Although there are few documented cases of people dying from an electric shock, such a situation could happen, a single discharge could incapacitate a person long enough to cause him to drown, even in shallow water. Multiple shocks can cause a person to stop breathing or suffer from heart failure.
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Electric eels will jump out of the water to attack.
Recent studies have found that electric eels will jump out of the water to attack predators, they just don´t stay below the surface. While manipulating electric eels with a net on a metal bar, Keneet Catania noticed that the eels attacked the bar when it approached, jumping from the water to hit it with electric shocks. In a series of experiments, Catania realized that this was not just a meaningless onslaught but a strategy. Catania noticed that the electric eels were coordinating their jumps with high voltage pulse discharges and when jumping, the eels progressively electrify large portions of the partially submerged target. The eels even bend their necks to stay in contact with the target, ensuring that any predators they are defending against feel their full wrath.
The development of electrical organs in electric eels occurs almost instantaneously after birth. There has been evidence that fish as small as 15 mm have started the development of electric organs. The reproduction process as such (which is sexually ) occurs during the year´s dry season. Females deposit a large number of eggs in the nest (thousands of them on average) that will be protected by a structure made by the electric eel male with his own saliva.
According to several studies carried out about the reproduction of the electric eels, it could be determined that the largest number of eggs of this species was found to be about 17,000. As for their average lifespan in the wild, it is still unknown, while when being under human care, males typically live 10 to 15 years, and females generally live 12 to 22 years.
Habitat and Distribution
Unlike true eels, electric eels live only in freshwater habitats, such as ponds and muddy streams. They are found only in the basins of the Amazon and the Orinoco in South America. They live in small pools and streams with stagnant water. The turbidity of the water does not bother them, since anyway they have a bad vision. Instead of sight, electric eels use low pulses of electricity to navigate their surroundings. They inhabit the bottom of these aquatic environments, but they have emerge to the surface to breathe every two minutes, unlike other fish that use gills and must remain submerged. They have gills but only use them to expel carbon dioxide and not to get oxygen from the water.
Both Amazon and Orinoco rivers have natural water´s fluctuation produced by precipitation patterns, resulting in two distinct seasons: wet and dry. The two seasons cause drastic changes in the habitat available for electric eels. During the rainy season, rivers swell, reconnecting lakes and lagoons as forests flood. Juvenile electric eels disperse and expand into new territories. As the water recedes in the dry season, large groups of fish are isolated in the pools and smaller streams that remain.
Water in these areas is poorly oxygenated, but electric eels are specially adapted to thrive in this environment. Throughout the dry season, the electric eels have an increased risk of predators, such as large mammals, which hunt outside the shallow waters they inhabit. Given the small space to retreat, eels are often forced to defend themselves. However, the water efficiently conducts electricity, providing a large surface area for applying the electric discharge. This means that an electrical pulse delivered through water may not be as painful for a large predator as it is administered outside of water, but the heroines of our today´s article can jump out of the water, sliding their body against a partially submerged predator to attack from there.
What Do Electric Eels Feed On?
Regarding their diet, it is a carnivorous one. Once they reach adulthood, they eat a variety of species of fish and small invertebrates and to a lesser extent some types of amphibians. On the other hand, when the electric eels are still young, their diet is based on the eggs of other species, especially those of shrimps and crabs.
Remember that electric eels use their electric discharges to hunt, since In the dark and murky waters where they inhabit, prey can be difficult to spot, but they help on motion-sensitive hairs spread along their body (the lateral line system) that detect any slight pressure change in the surrounding water. When the eel suspects a prey item is nearby, it emits two rapid electric pulses, called a doublet. These pulses affect the muscles of their prey, making them twitch involuntarily and alerting the electric eel to their presence. With a series of high-voltage pulses (around 400 per second), the electric eels paralyze and consume their prey. This entire process happens so quickly that it is almost impossible for the human eye to observe it in detail.
Their Common Behavior
Electric eels aren´t aggressive fish and attacks on humans are extremely rare; in other words, they only discharge electricity when they feel threatened or for predation purposes. They are nocturnal species which prefer dark waters despite their poor vision, since they use electro-localization to detect their prey.
In the IUCN Red List, the electric eels are classified as a species of «Minor Concern», but despite their ability to ward off predators by electric shocks, they are usually pried on by some collectors who keep them as pets or sell them to aquariums.
Fishing Electric Eels
At the moment of fishing electric eels it is necessary to take into account several aspects, such as their huge reactions when they are under threat or danger. First thing you should avoid is to touch them or pick them up without the proper protection or care.
Another aspect that must be considered is the force that they can apply at the time of being caught, which is why it is more difficult to capture electric eels in their natural habitat, where they tend to apply all their defense mechanisms. Once captured, take care when maintained when extracting the hook, to avoid possible accidents.
In many cases, the electric eels are confused with the marine eels, which are teleost fish belonging to the Anguilliformes order. In this sense we must be careful with the differences since in the electric eels belong to the Gymnotidae fish family and the Gymnotiformes order.
For this reason these species should not be confused since they are part of different taxonomies, and in spite of sharing physical characteristics they are totally different species. In the case of marine eels, they inhabit the world´s main seas and oceans although they can also live in fresh water as rivers. Among their main characteristics we can mention that they have an elongated shape similar to that of electric eels and that they can measure on average between 70 centimeters and up to 2 meters.
In this case, we have one of the differences between both species,since marine eels have sexual dimorphism (usually female are usually larger in size than in the case of males), while in the case of electric eels, both genera maintain very similar characteristics without presenting greater variations in size.
On the other hand marine eels are also known because of their body covered with a kind of mucous secretion, which gives them the ability to be more elusive, being one of their main defense mechanisms against their possible predators. so despite their physical characteristics very similar to those of electric eels, the marine eels aren´t able to generate electric shock.
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