Electric eel is a mysterious and dangerous fish that lives in the shallow muddy rivers of the northeastern part of the South American continent. It has nothing to do with common eels, being a hymn-shaped fish. Its main feature is the ability to generate electric charges of various strengths and purposes, as well as to detect electric fields.
Habitat
Over thousands of years of evolution, electric eels have adapted to survive in the extremely unfavorable conditions of overgrown and silted water bodies. Its usual habitat is stagnant, warm and muddy fresh water with a large oxygen deficiency.
The eel breathes atmospheric air, so every quarter of an hour or more often it rises to the surface of the water to capture a portion of air. If you deprive him of this opportunity, he will suffocate. But without any harm, an eel can go without water for several hours if its body and mouth are hydrated.
Description
The electric eel has an elongated body, slightly compressed from the sides and back, rounded in front. The color of adults is greenish-brown. Throat and lower partflattened head - bright orange. A characteristic feature is the absence of scales, the skin is covered with mucus.
Fish grows on average up to 1.5 m in length and weighs up to 20 kg, but there are also three-meter specimens. The absence of a ventral and dorsal fin enhances the resemblance of an eel to a snake. It moves in wave-like movements with the help of a large anal fin. Equally easy to move up and down, back and forth. Small pectoral fins act as stabilizers when moving.
Leads a solitary lifestyle. Most of the time he spends at the bottom of the river, frozen among thickets of algae. Eels are awake and hunt at night. They feed mainly on small fish, amphibians, crustaceans, and if you're lucky, birds and small animals. The victim is swallowed whole.
Unique Feature
In fact, the ability to create electricity is not some extraordinary feature. Any living organism can do this to some extent. For example, our brain controls muscles with electrical signals. An eel produces electricity in the same way as the muscles and nerves in our body. Electrocyte cells store the charge of energy extracted from food. The synchronous generation of action potentials by them leads to the formation of short electrical discharges. As a result of the summation of thousands of tiny charges accumulated by each cell, a voltage of up to 650 V is created.
Eel emits electric charges of various power and purpose:impulses of protection, catching, rest and search.
When at rest, it lies on the bottom and does not generate any electrical signals. Hungry, it begins to swim slowly, emitting pulses of up to 50 V with an approximate duration of 2 ms.
Having found the prey, it sharply increases their frequency and amplitude: the intensity increases to 300-600 V, the duration is 0.6-2 ms. A series of pulses consists of 50-400 bits. Sent electrical discharges paralyze the victim. To stun small fish, which the eel mainly feeds on, it uses high-frequency pulses. Uses pauses between discharges to restore energy.
When an immobilized prey sinks to the bottom, the eel calmly swims up to it and swallows it whole, and then rests for a while, digesting food.
Defending itself from enemies, the eel emits a series of rare high-voltage pulses in the amount of 2 to 7, and 3 small amplitude search engines.
Electrolocation
Eel's electric organs are not only for hunting and protection. Weak discharges up to 10 V are used for electrolocation. The eyesight of these fish is weak, and in old age it worsens even more. They receive information about the world around them from electrical sensors located throughout the body. In the photo of the electric eel, its receptors are clearly visible.
An electric field pulsates around a swimming eel. As soon as any object, such as a fish, a plant, a stone, is in the field of action,field shape changes.
Catching with special receptors the distortion of the electric field created by him, he finds a way and hiding prey in the muddy water. This hypersensitivity gives the electric eel an advantage over other species of fish and animals that rely on sight, smell, hearing, touch, taste.
Electric acne organs
Generation of discharges of different power is produced by organs of different types, occupying almost 4/5 of the length of the fish. In the front of his body is the positive pole of the "battery", in the tail area - the negative. Man's and Hunter's organs produce high voltage pulses. Discharges for the implementation of communication and navigation functions are generated by the Sachs organ located in the tail. The distance at which individuals can communicate with each other is about 7 meters. To do this, they emit a series of discharges of a certain type.
The highest discharge of electric eels recorded in fish contained in aquariums reached 650 V. In fish of a meter length, it is no more than 350 V. This power is enough to light five light bulbs.
How eels protect themselves from electric shock
The voltage generated by an electric eel during hunting reaches 300-600 V. It is deadly for small inhabitants like crabs, fish and frogs. And large animals such as caimans, tapirs and adult anacondas prefer to stay away from dangerous places. Why electricdon't eels shock themselves?
The vital organs of the fish (brain and heart) are located close to the head and are protected by adipose tissue, which acts as an insulator. The same insulating properties have his skin. It has been observed that when the skin is damaged, the vulnerability of fish to electric shocks increases.
Another interesting fact has been recorded. During mating, eels generate very powerful discharges, but they do not cause damage to the partner. A discharge of this power, produced under normal conditions, and not during the mating period, can kill another individual. This indicates that eels have the ability to turn the shock protection system on and off.
Reproduction
Eels spawn during the dry season. Males and females find each other by sending impulses in the water. The male builds a well-hidden nest from saliva, where the female lays up to 1700 eggs. Both parents take care of the offspring.
The skin of the fry is of a light ocher shade, sometimes with marble stains. The first hatched fry begin to eat the rest of the eggs. They feed on small invertebrates.
Electrical organs in fry begin to develop after birth, when their body length reaches 4 cm. Small larvae are able to generate an electric current of several tens of millivolts. If you pick up a fry that is only a few days old, you can feel the tingling from electrical discharges.
After growing up to 10-12 cm in length, juveniles begin to lead an independent lifestyle.
Content incaptivity
Electric eels do well in captivity. The life expectancy of males is 10-15 years, females - up to 22. How long they live in the natural environment is not known for certain.
The aquarium for keeping these fish should be at least 3 m long and 1.5-2 m deep. It is not recommended to change the water in it often. This leads to the appearance of ulcers on the body of the fish and their death. The mucus that covers the skin of acne contains an antibiotic that prevents ulcers, and frequent water changes appear to lower its concentration.
In relation to representatives of its own species, eels, in the absence of sexual desire, show aggression, therefore, only one individual can be kept in an aquarium. Water temperature is maintained at 25 degrees and above, hardness - 11-13 degrees, acidity - 7-8 pH.
Is eel dangerous for humans
Which electric eel is especially dangerous for people? It should be noted that for a person a meeting with him is not fatal, but can lead to loss of consciousness. The electrical discharge of the eel leads to contraction and painful numbness of the muscles. The discomfort may last for several hours. Larger individuals have more current, and the consequences of being struck by a discharge will be more deplorable.
This predatory fish attacks without warning even a larger opponent. If an object enters the range of its electric field, it does not swim away and does not hide, preferring to attack first. Therefore, approaching a meterEel closer than 3 meters, in no case can not.
While fish is a delicacy, catching it is deadly. Local residents have invented an original way of catching electric eels. To do this, they use cows, which tolerate shocks of electrical discharges well. Fishermen drive a herd of animals into the water and wait for the cows to stop mooing and rushing about in fear. After that, they are driven out onto land, and they begin to catch already harmless eels with nets. Electric eels cannot generate current indefinitely, and the discharges gradually become weaker and stop altogether.
