The electric eel is a dangerous and mysterious creature. Its main feature is the ability to reproduce the electric field, which it uses not only for navigation, but also for hunting and for protection from external enemies. With an ordinary eel, it is related only by the presence of an elongated body and a powerful anal fin, with which it controls its movements. According to the international classification, the electric eel belongs to a special order of ray-finned fish – hymnoid.
The origin of the species and description
Since the distant ancestors of modern fish did not have bones or other solid formations, traces of their existence were easily destroyed by nature itself. Under the influence of geological cataclysms, the remains decayed, collapsed and eroded. Therefore, the history of the origin of any kind of fish is only a hypothesis of scientists based on rare geological finds and a general idea of the origin of all life on Earth.
At the beginning of the Cretaceous period, a group of cyprinids separated from ancient herring-like fish, which they chose for comfortable living fresh tropical waters. Then they spread to all continents and went out to sea. Until recently, electric eels also belonged to the Cyprinidae family, but in the modern classification they are classified as a special order of ray-finned fish, to which scientists have given the name “gymnotoides”.
Video: Electric Eel
The uniqueness of the representatives of hymnoids lies in the fact that they produce electric charges of various strengths and purposes. Electric Eel is the only one that uses this ability not only for electrolocation, but also for offense and defense. Like its closest relatives, it has a long narrow body and moves in the water with the help of a large and highly developed anal fin.
The electric eel needs atmospheric air to breathe, so it periodically floats to the surface to take another breath . But he can easily go without water for a while if his body is sufficiently hydrated.
The electric eel is a predator, and in its usual habitat it behaves quite aggressively, attacking even a larger rival. There are many known cases of human injury by an electric charge emitted by an eel. If the individual is small, then such an impact does not pose a danger to human life, but causes loss of consciousness, unpleasant and painful sensations. A large eel that produces a lot of current can cause serious harm to a person, so meeting him is extremely dangerous.
Appearance and features
The appearance of an electric eel is often compared to that of a snake. The similarity lies in the elongated shape of the body and the wavy way of moving. The eel's body is completely devoid of scales. It is completely smooth and covered with mucus. Nature has endowed the electric eel with natural camouflage in the form of a brown-green color, which is absolutely not noticeable in muddy waters against the background of a muddy bottom – in the favorite habitat of these fish.
A powerful fin located in the back of the body is responsible for the movement of the electric eel. Two more small pectoral fins act as movement stabilizers. The fish has no ventral, dorsal, or caudal fins. The electric eel is a large fish. Its body has a length of about one and a half meters, the average individual weighs about 20 kg. But there are also three-meter individuals weighing up to 40 kg.
Unlike their underwater counterparts, the eel breathes not only oxygen dissolved in water, but also atmospheric air. For this purpose, he is forced to come up to the surface every fifteen minutes (or more often) to take another breath. Since the oral cavity accounts for most of the oxygen uptake (approximately 80%), during evolution, a mucous membrane with increased perfusion has formed in the almost toothless mouth of the eel. The remaining 20% of oxygen uptake is provided by the gills. If an eel is denied access to atmospheric air, it suffocates.
But the main feature of these fish is the generation of electrical discharges of varying degrees of power. In the body of an electric eel there are special organs responsible for the generation of electricity. For clarity, you can imagine an eel in the form of an electric “battery”, the positive pole of which is in the head area, the negative one in the tail area.
The voltage, frequency and amplitude of the generated pulses vary depending on their purpose:
Minimum current – less than 50 V – reproduced for searching and detecting prey, the maximum is about 300-650 V – during the attack.
Where the electric eel lives
Electric eels are widespread in the northeastern part of South America, in the Amazon basin. They inhabit the Amazon itself, the Orinoco River, as well as their tributaries and oxbow lakes. Fish mainly live in muddy and silty muddy water with rich vegetation. In addition to rivers and streams, they also inhabit swampy reservoirs. All their habitats are characterized by low oxygen content. Therefore, eels have been gifted by nature with the adaptive ability to absorb oxygen through their mouths on the surface of the water.
In the process of adapting to a dirty and muddy environment, the electric eel has developed other unique abilities. Extremely limited visibility, for example, is overcome by the ability for active low-electrical communication. Animals use their electric organs for territorial differentiation and search for partners, as well as for orientation.
The electric eel lives only in fresh waters, like most of its potential prey. This “homebody” rarely changes its place of residence if there is enough food in the chosen territory. However, observations of the behavior of the electric eel during the mating season indicate that individuals can leave their usual places, moving away for the time of mating to inaccessible areas, and return back with already grown offspring.
Now you know where the electric eel lives . Let's see what he eats.
What does the electric eel eat
The main diet of the electric eel is made up of medium-sized marine life:
Small mammals and even birds often come to him for lunch. Young animals do not disdain insects, and adults prefer a more impressive meal.
Hungry, the eel begins to swim, emitting weak electrical impulses with a power of no more than 50 V, trying to detect the slightest wave vibrations that can betray the presence of a living being. Having found potential prey, it sharply increases the voltage to 300-600 V, depending on the size of the victim, and attacks it with several short electrical discharges. As a result, the victim is paralyzed, and the eel can only calmly deal with it. He swallows prey whole, after which he spends some time in a motionless state, digesting food.
The strength of the electric shocks produced by the eel is regulated in such a way as to literally force the prey to leave the shelter. The trick is that the electric current activates the victim's motor neurons and therefore generates involuntary movements. Electric eel has a whole arsenal of various electric shocks, so it successfully copes with this task.
In order to study the behavioral characteristics of the electric eel, scientists dissected the dead fish with electrical conductors to make it, like real prey, flinch during the discharge, creating movement in the water. In various experiments with such prey patterns, they found that flinching determined the targeting of an attack on an immobilized prey. The eels attacked the fish only when it reacted to the electric shock. On the contrary, visual, chemical or sensory stimuli alone, such as the movements of the water of a writhing fish, did not achieve their goal.
Character and lifestyle features
Electric eel is a rather aggressive creature. At the slightest sense of danger, he attacks first, even if there is no real threat to his life. Moreover, the action of the electric discharge emitted by it extends not only to a specific target, but also to all living beings that find themselves in the range of the electric impulse.
The nature and habits of the electric eel also determines its habitat. Muddy muddy waters of rivers and lakes force him to be cunning and use all his hunting arsenal to get his own food. At the same time, having a well-developed electrolocation system, the eel is in a much better position than other underwater inhabitants.
Interesting fact: The eyesight of an electric eel is so weak that it practically does not use it, preferring to navigate in space using electrical sensors located throughout the body.
Scientists continue to study the generation process the energy of these amazing creatures. A voltage of several hundred watts is generated by thousands of electrocytes, muscle cells that store energy from food.
But the animal can also generate weak electrical currents, such as when choosing a mate. It is not known for sure whether the eel uses metered electricity when in contact with a partner, as it does to hunt fish and invertebrates in the water. However, it is known that the animal uses its electric shocks not only for sudden paralysis and killing of victims during the hunt. Rather, he uses them on purpose and doses them accordingly to control his target remotely.
It uses a dual strategy: on the one hand, it generates mild electric shocks to spy on its prey, locate it, and read its target's electrical profile. On the other hand, high voltage shock is his ultimate weapon.
Social structure and reproduction
Electric eels seek their mating partner through power surges. But they produce only weak discharges that can be picked up by a possible partner in muddy water. The mating season usually falls on the time period from September to December. The males then build nests from aquatic plants while the females lay their eggs. There are usually about 1,700 eggs in a clutch.
Interesting fact: During mating, the powerful discharges generated by the eel do not harm the partner. This indicates that they have the ability to turn the electric shock protection system on and off.
Both individuals guard their nest and eggs, and later – larvae, sometimes reaching ten centimeters already at the time of hatching. The skin of the fry is light green in color, heterogeneous, with marble stains. Those fry who were lucky enough to hatch first eat the rest of the eggs. Therefore, no more than a third of fry survive from a clutch of 1700 eggs, the rest of the eggs become the first food for their fellows.
Young animals feed mainly on invertebrates, which they can find on the bottom. Adult eels usually prey on fish, recognizing them with weak electrical shocks and paralyzing the prey with strong electric shocks before swallowing. Some time after birth, eel larvae are already able to generate low-voltage electric current. And young animals begin to lead an independent lifestyle and make their first attempts to hunt at the age of a few weeks.
Interesting fact: If you pick up a fry that is only a few days old, you can feel tingling from electrical discharges.
Electric eel's natural enemies
The electric eel has such a perfect defense against attack that in its usual habitat it has practically no natural enemies. Only a few cases of confrontation between electric eels and crocodiles and caimans are known. These predators do not mind eating the eel, but they have to reckon with its unique ability to generate powerful electrical discharges. Despite the rough and thick skin of a crocodile, they can harm even a large representative of reptiles.
Therefore, most underwater and terrestrial animals prefer to stay as far as possible from those places where electric eels live and avoid even an accidental meeting with them. The consequences of an electric shock emitted by an eel are indeed extremely unpleasant – from temporary paralysis and painful spasms to death. The strength of the damage directly depends on the power of the electric discharge.
Given these facts, we can assume that the main natural enemy of the electric eel was and remains a person. Although the meat of this representative of the marine fauna cannot be called a delicacy, the scale of its capture is quite large.
Interesting fact: Hunting for an electric eel is a very difficult and extremely dangerous business, but fishermen and poachers have found an original way of mass fishing. In the place of the greatest accumulation of electric eels in shallow water, they drive a small herd of cattle – cows or horses. These animals quite calmly endure the shocks of electric discharges of the eel. When the cows stop tossing about in the water and calm down, it means that the eels have finished their attack. They cannot generate electricity indefinitely, the impulses gradually weaken and, finally, completely stop. At this moment, they are caught, without fear of getting any serious damage.
Population and species status
With such a large habitat area is difficult to judge the actual size of the electric eel population. Currently, according to the World Conservation Union (IUCN), the species is not listed as an extinction risk zone.
Despite the fact that the electric eel has practically no natural enemies and is not yet at risk of extinction, various factors of human intervention in the ecosystem of its habitat expose the existence of this species to significant threats. Overfishing makes stocks of its prey vulnerable. Especially when you consider that the tropical freshwater ecosystems of South America are very sensitive to the slightest interference and can be destroyed even with small interference.
Reservoirs and their inhabitants are exposed to mercury poisoning, which is uncontrollably used by gold miners to separate gold from river sediment deposits. As a result, the electric eel, as a carnivore at the top of the food chain, is exposed to the greatest poisoning. Dam projects also affect the habitat of the electric eel by significantly changing the water supply.
WWF and TRAFFIC projects to protect the flora and fauna of the Amazon Protecting the habitat of all endangered species of animals and plants in the Amazon has an absolute priority. Therefore, WWF has set itself the goal, over the next ten years, of securing much of the biodiversity of the Brazilian Amazon through an extensive network of protected areas.
To achieve this, WWF is working on many levels to save the Amazon rainforest. As part of a WWF initiative, the Brazilian government pledged in 1998 to protect ten percent of the Brazilian Amazon rainforest and developed one of the most ambitious conservation programs in the world, the Amazon Region Protected Areas Program (ARPA). The implementation of this program has absolute priority for WWF. In total, the program is to provide permanent and complete protection to 50 million hectares (approximate area of Spain) of rainforest and water bodies.
The electric eel is a unique creature. It is deadly not only for representatives of the animal world, but also for people. On his account there are more human victims than on the account of the notorious piranhas. It has such a formidable self-defense system that even studying it for purely scientific purposes is incredibly difficult. Nevertheless, scientists continue to monitor the life of these amazing fish. Thanks to the accumulated knowledge, people have learned to keep this formidable predator in captivity. And in the presence of comfortable living conditions and enough food, the electric eel is quite ready to get along with a person if he, in turn, does not show aggression or disrespect.