In the crevices of the rocks, a colorful mantis shrimp lurks here, wearing dark green armor, orange-red between the head and chest, and a white stripe like a honeycomb on the edges. A crab passed in front of the rock, suddenly, the mantis shrimp in the crack of the rock struck, only to hear a bang, a pair of forelimbs that seemed to be wearing boxing gloves knocked on the crab with lightning speed, fortunately, the crab had been protecting the crab claws in front of him, blocking the fist of the mantis shrimp, but the crab was not happy, and the crab claw that blocked the fist had been smashed from the middle. The crab fled in a hurry after leaving a pliers, and the mantis shrimp with a tail of mantis also collected it when it saw it, dragging half a crab claw back between the stone crevices.
One punch breaks the crab claws
The mantis shrimp has a colorful shell, with a variety of shades such as blue, green and red, and its unique tail is very similar to the tail feathers of the peacock, so it will be kept as a pet by some people. However, although the mantis shrimp is beautiful, it is a fierce character, and the most talked about is its powerful pair of "iron fists".
The individual of the mantis shrimp is not large, only 3 to 18 cm, the largest is not more than the palm of an adult, and the weight is only 60 grams. Such a petite body, the mantis shrimp can punch 60 kilograms of fists in 2 milliseconds, which is equivalent to 500 punches in a second. The top speed of the mantis shrimp is more than 80 km /h, like a high-speed car, the acceleration is equivalent to a bullet of 0.22 calibers, and the force is equivalent to 1000 times their own weight. At present, the recognized limit of human reaction speed is 100 milliseconds, and only with the help of high-speed cameras can we see the moment when the mantis shrimp punches.
Moreover, the fist of the mantis shrimp will produce a bubble in front of the fist after hitting it for half a millisecond. Don't underestimate this bubble, it is when the mantis shrimp punches, the high-speed water flow that is pushed away makes the water pressure drop extremely fast, and it is formed after the water is vaporized. This is known as the cavitation phenomenon, which often occurs on the propeller pulp of ships, and these small bubbles produce a huge shock wave when they burst, which can blow out small holes in the propeller of steel.
Damage to the propeller by cavitation
The bubbles produced by the cavitation phenomenon will burst in a very short time and emit a huge explosion sound, producing light and heat at the same time, and the temperature in that instant is enough to reach more than 6700 degrees Celsius, which is about equal to the temperature of the sun's surface. The mantis shrimp can bring two attacks with one punch. Even if you fail to hit the prey with your fist, the subsequent air cavitation phenomenon will cause damage to the prey. In a less appropriate metaphor, is the mantis shrimp like a "martial arts master" who hurts people in the air?
Hit by the fist of the mantis shrimp, not only the crustaceans such as crabs can not stand up, even the glass of the ordinary fish tank can not stand up, so there is also a saying that if you want to raise the mantis shrimp, you must first prepare a bulletproof fish tank. Such a powerful fist, it is no wonder that it is called "The King of Underwater Boxing".
Why can't the mantis shrimp be cooked at 6700°C?
The mantis shrimp can punch 60 kilograms of fists, and the temperature generated by the subsequent air cavitation phenomenon can reach the surface temperature of the sun. So why aren't they cooked by boiling seawater or killed by recoil?
When the bubbles produced by the mantis shrimp burst, the temperature can be compared to the surface of the sun, which sounds very exaggerated, if there is such a high temperature, the mantis shrimp has not cooked itself earlier?
In fact, the temperature here is the ultimate temperature of the bubble bursting moment, the temperature is not equal to the heat, the energy of the bubble itself is not high, the bubble rupture time is extremely short, the temperature can not be maintained for too long, and the surrounding is seawater, the heat generated by the cavitation phenomenon is transmitted to the seawater and the seawater temperature will not rise to the boiling point, and naturally will not hurt the mantis shrimp itself.
The fist of the mantis shrimp can be damaged after 50,000 high-intensity strikes, relying on the special structure of its fist. The outermost layer of the fist of the mantis shrimp has a hard shell, and its composition contains a high concentration of mineral components similar to bone components.
But just hard is not enough, in order not to hurt themselves, mantis shrimp must also reduce the counter-shock when the fist attacks,
Three-tier structure
Inside the fist of the mantis shrimp, it is divided into two areas. The first area is distributed with a spiral-shaped fibrous substance that increases the cushioning force to slow the vibration and absorb energy, like a boxer's glove. The second area, known as the "stripe zone," is highly arranged with fibrous matter, just as boxers would wrap bandages around their hands, and the role of this part is not to absorb energy, but to protect themselves, by pressing the bones to prevent breakage. The combination of these two areas minimizes the anti-shock damage caused by punches.
But even so, the mantis shrimp cannot completely ignore the damage caused by the punch, after all, the air cavity phenomenon can even explode the steel propeller to blow out dense pits. So what to do? There is another way for the mantis shrimp - molting. The limit of the mantis shrimp's fist strike is 50,000 times, but it will not wait for its fist to be completely damaged, and about every three months, it will molt to compensate.
The molting period is its most vulnerable time, but the mantis shrimp is still as aggressive as before, as if its pride does not allow it to back down, after all, even the 9-day-old small finches tail mantis shrimp can rely on its fists to prey on small fish and shrimp. After the newborn shell hardens, the mantis shrimp becomes back to the king of the underwater boxer.
See what humans can't see
In addition to its strong boxing ability, the mantis shrimp has very special eyes, with the most complex visual system among animals in the world, and can see the world that humans can't see.
The mantis shrimp has a compound eye like a fly, and has an eye stalk under the eye, so it can rotate independently and look at different places. And it also has small black holes in its eyes, which are actually equivalent to human pupils, but such "pupils" finches-tailed mantis shrimp have six.
In the compound eye of the mantis shrimp, it has 3 layers of photosensitive cells that can respond to light of different wavelengths. Human photoreceptors are actually only red, green, blue 3 kinds, through the different proportions of these three colors, to see the world we see now, so these three colors are also called optical primary colors.
However, the mantis shrimp has a full 16 different photoreceptors, of which 9 are used to "see" visible light, 3 are used to "see" ultraviolet light, and the rest are used to "see" infrared light. And the light-sensitive cells of the mantis shrimp can also process information independently, which means it can see both ultraviolet and infrared light. The dark world for humans may be a different story for the mantis shrimp. The colors of the world that mantis shrimp see may never be imaginable for humans.
The carapace structure and special visual structure of the mantis shrimp have also given scientists a lot of inspiration, its carapace structure is light and strong, and full of toughness, and its comprehensive performance even exceeds many hard artificial ceramics, which is of great significance to all walks of life. Through the study of the eye structure of the mantis shrimp, a sensor that can sense red, green, blue and 3 kinds of near-infrared light has been invented, which has played a huge role in the medical industry.
Resources
"Mantis shrimp in multicolored armor The fastest killing speed in the ocean, fist like a bullet out of the chamber" Zhang Taolahan
"The Strange Visual Perception of Mantis Shrimp" Liu Bowen
"The Magic Mantis Shrimp" Zhang Shouzhong
"This shrimp is amazing!" Guiding oncologists to "see" cancer cells" Science Popularization China