Rays are cartilaginous fish, round or oval, with small mouth and eyes. It lives in tropical and subtropical coastal waters, distributed in the East China Sea and South China Sea of China. It often semi-buries its body in the sand or crawls along the seabed.
There is an oval generator between the torpedo's head and pectoral fin, which is composed of specialized muscles. The generator is composed of several muscle fibers, forming a hexagonal cylindrical tube with colorless colloidal substances in it, which mainly plays an electrolytic role. There are many flat plates arranged in the pipe. These plates are made up of small chemical cells connected to nerves. We call them "plate cells". When the torpedo catches food, the signal is transmitted to the cells of the electric plate through the nerve, and the small cells produce chemicals, which change the charge distribution inside and outside the cell membrane and produce potential difference and current. The current generated by the battery is very small. There are millions of batteries on the torpedo. When they discharge at the same time, the current is quite large. Giant rays, living in tropical and subtropical coastal waters of the Atlantic Ocean and Indian Ocean, are relatively large, up to more than 2 meters. Scientists have tested this torpedo and found that it can generate 60 volts, 50 amperes of electric pulses and 3000 watts of electric shock, enough to kill a big fish of dozens of kilograms.
The world's first artificial battery-Volta battery. It is designed according to the model of torpedo power generation device.
Electric eels are very similar to ordinary eels, with a body length of more than 2 meters and a weight of more than 20 kilograms. Living in the Amazon River and Orinoco River in South America.
The electric eel has two pairs of generators, which are long spindle-shaped and located on both sides of the caudal spinal cord. The average voltage of electric eel during discharge is above 350 volts, but there are also records of 650 volts discharge. The highest voltage of electric eels in the United States exceeds 800 volts, which is enough to kill a cow. The current generated by electric eel discharge is very weak, generally less than 1 amp; But sometimes a short-term discharge with a voltage of 500 volts and a current of 2 amps, that is, a power of 1000 watts, is observed. Although direct current is emitted, the discharge frequency can reach 300 pulses per second. The destructive power of electric discharge depends on the size of eel and the condition of organism. When the electric eel is less than 1 meter long, the voltage increases with the growth of the electric eel. When it increases to 1 m, it only increases the intensity of current. When the electric eel preys, it swims quietly near the school of fish, and then it can continuously emit current. The electric shock fish immediately fainted and became stiff, so the electric eel took the opportunity to swallow them. Electric eels discharge sometimes not necessarily for predation, but also for physiological needs. The fish electrocuted by electric eel often exceeds the amount needed to eat, which brings harm to fishery production. After the electric eel is discharged, it takes some time to recover before discharging. Taking advantage of this feature, when fishermen catch electric eels, they first drive livestock into the water to discharge the electric eels, and then catch them to avoid fishermen's injuries.
Electric catfish is also a kind of fish that can generate electricity. The electric catfish lives in the Nile River in Africa. It looks like a catfish. Its body length is about 1 m, and its mouth has three pairs of beards. It has no dorsal fin and has a very low and flat fat fin at the bottom of its tail. The electric catfish has a pair of generators, which are located under the skin of the back. It produces a voltage as high as 350 volts, which can make people and livestock dizzy.
Of course, not all electric fish can generate strong electricity. There are some fish in the ocean that can emit weak current. Their power generating organs are very small, and the maximum voltage is only a few volts. They can't kill or stun other animals, but they can be used to explore the environment and find food like complex underwater radar. These fish are covered with sensing organs, and they can receive the returning electric waves. Because any living thing has strong and weak bioelectricity, the electrosensors of these fish can feel very weak electric field changes.
Sharks are very sensitive to changes in electric fields. Using this, scientists invented the "electronic shark repeller", which can drive sharks away from 1 ~ 10 meter by DC pulse. Divers carrying these instruments can avoid shark attacks underwater.
Catfish can prevent earthquakes. The sudden change of ground current before the earthquake stimulated the electric receptors of catfish, making them feel scared and jump around, so we can find a new method to predict earthquakes through the study of catfish.
In a word, the discharge of fish is an adaptive ability to defend and attack enemies and catch food acquired in the process of evolution. If human beings can use bionics to simulate the power generation organs of electric fish to generate electricity in the ocean, then the power problems of ships and submarines can be well solved.
-"Walking in the Ocean Aquarium" by Ma Yingjie and Ma Aijun, Ocean Press, 20065438+0;
Why does the electric eel discharge?
From 65438 to 0989, an interesting retrospective exhibition of "Clock" was held in the French Science City. A clock driven by electricity released by charged fish has aroused great interest. This charged fish discharges regularly, and the direction of current changes every minute, so it is called "natural clock".
Common charged fish are electric eel, ray, catfish and so on. Among them, the strongest "electricity" is electric eel. Its discharge voltage can reach 300-500 volts, which is enough to electrocute nearby fish, and people and animals will be paralyzed. According to the calculation, the electric energy of 1 0,000 electric eels is gathered together, which is enough for 1 electric locomotive to run for several minutes.
The electric eel looks like a snake. It is about 2 meters long and weighs about 20 kilograms. It lives in rivers in South America, Central America and other places, often lying motionless at the bottom of the water, and occasionally surfaced to breathe. It feels the change of the surrounding environment through "inductance". Once it finds its prey, it will kill or stun it by electric discharge, and then have a full meal. Because the electric eel has such a unique skill of killing prey, it is called "the devil in the river".
How does the electric eel discharge?
It turns out that the electric eel is a living "generator". The muscles on both sides of its tail are composed of 6000- 10000 regularly arranged muscle slices separated by connective tissue, and many nerves directly lead to the central nervous system. Each muscle slice is like a small battery, which can only generate a voltage of150mV, but nearly ten thousand "small batteries" connected in series can generate extremely high voltage.
The electric current in the tail of the electric eel flows to the receptor in the head, so a weak electric field is formed around its body. There are special cells in the central nervous system of electric eel to monitor the activities of electric receptors, and can command the behavior of electric eel according to the results of monitoring and analysis, and decide to adopt predation behavior, avoidance behavior or other behaviors. Someone has done an experiment: put two vertical wires in a pool, put an electric eel in it and put the pool in a dark environment. It was found that the electric eel always shuttled between wires without touching them at all. When the wire was electrified, the electric eel suddenly ran back. This shows that electric eels rely on "inductance" to judge the surrounding environment.
After the electric eel discharges the electric energy stored in the body, it will take some time to accumulate before it can continue to discharge. Therefore, when catching electric eels, Brazilians always drive livestock into the river to lure electric eels to discharge, or use trawls to make electric eels discharge online, and then easily kill electric eels that have lost their counterattack ability.