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Electric Eel - The Most Powerful Electric Fish
Electric eel is one of the few electric animals in the world and one of the few hundreds of fish that can generate, store and discharge electricity for killing their prey (hunting) or to keep predators away (self-defence) and for sensing and communication. It is an electric fish and a carnivore that lives in the fresh waters of South America. They are the only species in the genus Electrophorus.
The characteristics of the electric eel do look frightening to me, as they resemble that of a serpent, however, what triggered me to read and write about them, is the scene from the movie “Journey 2: A journey to the mysterious island”, where Hank uses the voltage generated from an electric eel to power up the submarine. Yes, this may not be something that can happen for real, but there is a fact that the electric eel can produce a high voltage electric charge.
Hank vs The electric eel
Electric eels are not actually eels, but are ostariophysians and are closely related to the catfish family (neotropical knifefish). They get their name from the huge amount of electric charge they can generate to stun their prey and keep their predators at bay.
They are not under any threats with their population being steady or stable and so are on the least concern (LC) on the IUCN red list.
Scientific Classification (Taxonomy):
Species: Electrophorus electricus
Abbreviation and Explanation of terms used:
EOD - Electric Organ Discharge
Electrocytes – A modified striated muscle that does not contract, but produces electric signals; the component of the electric organ in some fish
Electroplaque or electroplax – one of a number of plates forming an electric organ in fish, consisting of modified muscle tissue having an electric charge
Electrocute – Kill by electric shock
Electrogenic - Producing a change in the electrical potential of a cell
Gymnotiformes – bony fishes commonly known as the Neotropical or South American knifefishes that have long bodies and swim using movements of their elongated anal fin
Weberian apparatus – anatomical structure that connects the swim bladder to the auditory system in fishes belonging to the Superorder Ostariophysi
Ostariophysians – fish species whose swim bladders divide into two chambers
Neotropical – Relating to or denoting a phytogeographical kingdom comprising Central and South America excluding southern Chile and Argentina
Oviparous – Egg-laying
Ref: Wikipedia and WordWeb
Characteristics and Behaviour of the Electric Eel:
- The electric eels grow up to a length of 1.8 to 2.5 m and can weigh up to 20 kg. Their bodies are long and cylindrical in shape with a flat head (they resemble a serpent :-o). They are the largest species of Gymnotiformes.
- Their upper body is dark greenish brown or dark blue, or black or dark purple or dark grey in colour and the lower body is yellowish or orange in colour and this helps with camouflage.
- Mature males have a darker lower body.
- The females are much larger than the males and these fish have no scales.
- Their mouth is large and highly vascularised and is located at the end of the snout.
- The anal fin is located along the length of the body till the tip of the tail that helps with locomotion.
- They do not have caudal, dorsal and pelvic fins and are not fast movers.
- They have a swim bladder that consists of two chambers.
- Anterior chamber: Connected to the inner ear and this increases its ability to hear.
- Posterior chamber: Runs along the length of the fish’s body and is used when the fish surfaces the water to breathe
- They have small eyes and their eye-sight is poor and hence they use a low electric power or charge of about 10 volts like a radar to navigate and sense their prey. Also in muddy waters where visibility is near zero they use the low voltage discharge to navigate, communicate and sense their prey.
- They have very good sense of hearing and this is through the Weberian apparatus that connects their ear to the swimming bladder. This helps with the increased hearing ability.
- They come to the surface of water for breathing every ten minutes. They gulp air and return to the bottom of the river and if they do not surface, they can drown and die. They stay on the surface for a very short time, just for a second or so. They take in oxygen from the air they take in this way and the carbon dioxide is released through its skin that is permeable.
- They have gills like other fish, but that does not help with breathing or oxygen intake.
- The vital organs of the electric eel are located in the anterior portion of the body which forms just 20% of the fish’s body and the rest of the 80% of the posterior body of the fish contain the electrical organs.
- The skin is thick and slimy and this helps as a protective layer from the electric current that they generate.
- Its body has bilateral symmetry.
- While the adult electric eels are capable of producing a voltage higher than 500 or 600 Volts, the young ones are reported to produce voltages of around 100 Volts.
- They can change the intensity of the electrical discharge depending on the need.
- The electric eels when disturbed can continuously produce shocks at intervals for at least an hour.
- They have tuberous receptors that are distributed on their body in patches and these help with hunting other Gymnotiformes.
- They are solitary animals and are nocturnal. The low level EOD was found to be higher in specimen in the night than during the day confirming that they are more active in the nights than during the day. They are found to prefer shady areas during the day.
Why do the electric eels have this adaptability or the ability of discharging electricity?
There are questions as to why the electric eel comes with an adaptability of generating electricity. The answer can be quite simple or straightforward. The electric eels do not have teeth. So they can feed only on prey that is not moving. If the prey is moving, it can slip away because there are no teeth to stop them from slipping away. So electric eel comes with this capability to stun its prey or even killing them before feeding on them.
Habitat, range, distribution and food of the electric eel:
The electric eels are found in the freshwaters like murky streams and ponds of the Amazon and Orinoco basins and other rivers of South America and are quite common in their habitat area.
They are found mostly in the northern parts of South America like the Guyanas, Orinoco rivers and the middle and lower Amazon basins mainly the northern parts of Brazil. They are also found in coastal plains, creeks, swamps and floodplains.
They are carnivorous and feed mainly on invertebrates, crustaceans, amphibians (e.g. frogs) and fish and sometimes on birds and other mammals. Hatchlings that are born first eat other eggs and embryos that are found from later batches of eggs or of different eels. The young eels feed on small invertebrates like shrimp and crabs.
How do the electric eels hunt?
The electric eels use the Sach’s organ that sends out weak electric pulses that help with movements and locating the prey. Once a prey is located, the message is sent to the brain that causes higher electric pulses from the Main organ and Hunter’s organ to be discharged that stun the prey. This does not always kill the prey, but stuns it sufficient enough for the eel to open its mouth and take the prey inside their mouth easily through suction.
Reproduction and lifespan of electric eel:
- The electric eels mate during the dry season. It is a fractional spawner and they lay three batches of eggs in succession during the spawning period.
- They have a very unusual breeding behaviour in which the male eel builds a nest out of his saliva (foam like) in the dry season in which the female eel lays her eggs. The male then fertilises them (external fertilisation).
- Thousands of eggs (around 16,000 to 17,000 eggs) are laid in one nest during the spawning season from which hatchlings hatch. The number of hatchlings will be far less compared to the number of eggs laid and this is due to the eggs being eaten by other predators.
- Male guards the hatchlings as they grow till mid January when the first rains flood the breeding area and disperse the young eels (about 10 cm long) around the habitat area. They defend the nest and the hatchlings with huge effort.
- The hatchlings are looked after by both the male and the females.
- They live up to 15 yrs in the wild and up to 22 years in captivity.
Development of electrical organs in the young eels:
The electric organs in young eels happen as soon as the hatchlings hatch. It has been evidenced that the young ones that were as small as 1.5 cm had electric organ developing, but initially this is used only for creating low discharge that help with movements, orientation, sensing etc. The high discharge electric organs develop only when the fish reach a size of about 4 to 5 cm.
Electric eels as pets:
Electric eels are difficult to catch due to their electric behaviour. A person, who wishes to collect one, will have to make the eel tired by continuously discharging its electricity till all of it is completely discharged, then get into water and catch one.
On a kind note: I personally think that the above activity is not fair on an animal for the mere pleasure of someone owning it as an exotic pet…!
Due to their huge size, they will also require a huge tank which is difficult to maintain. They cannot be grown with other fish as they will attack them, and the adult electric eels are mostly tolerant in between them. They are very hard to be looked after as the water in which they are kept needs to be maintained at a particular temperature and they can make the water dirty and smelly quite quickly. They are kept in zoos and aquariums.
World's Deadliest : Six-Foot Electric Eel
Threats to the electric eel:
The only threats are the specimen that are collected for studies, for aquarium trade and sometimes for human consumption (eaten by the locals in Amazon). However this has caused no decline in population and hence no conservation measures are put in place.
Facts about the electric eel:
- Electric eels are a type of knifefish and not really eels and their two forms of communication channels are acoustic and electric.
River Monsters- Lassoing an Electric Eel
- A group of electric eels is called a swarm
- The shock from an electric eel can be felt as far as 28 ft away in still water.
- They have been used as a model in the study of bioelectrogenesis
- Research has been conducted on developing the electrical behaviour of the cells in the electric eel as a power source for medical implants and other minute devices.
- Roughly 80% of the electric eel’s body is its tail where the electric organs are located.
- The electric eel does not have spine and no teeth in its mouth.
- The electric eel is the most powerful electric fish that can discharge a high voltage (500 to 650 V) at 1 ampere.
Electric Eel Audio Electrical Discharges
- Electric eels are capable of knocking down horses that are really powerful animals, while they cross the river and they can knock down or even kill humans.
- Although human death is rare from electric eels, a single shock can drown humans and multiple shocks can cause heart failure or failure of the respiratory system and can result in death.
- There are no sign of injuries or cause of death in a deceased person electrocuted by an electric eel.
- During dry seasons, eels that get trapped in small lakes or mud holes kill wandering nearby humans by electrocuting because they feel threatened. The humans could be killed due to repeated shocks from a single eel or from many eels
- A very interesting fact about these electric eels is that they continue to discharge electricity, even eight to nine hours after their death.
- Shock from an electric eel causes cardiac failure (heart fibrillation) and respiratory paralysis, this is because it alters the functions of the involuntary muscles. These symptoms can result in death.
- Since the electric eels surface to breathe, they can withstand water that is poor in oxygen.
- Electric eels have no predators due to the fact that they are deterred with their huge shocking abilities.
- The Amazon electric eel measures as long as 3 metres.
I hope that you found the information here useful and interesting. I would like to hear your experiences and other facts if any about this powerful creature.
Thank you for stopping by.