Also swimming in the water, why do some mammals swing their tails from side to side while mammals sw

There are many types of marine life in the ocean, including fish and mammals, such as whales and seals. Biological evidence and classification suggest that the ancestors of whales were artiodactyls, genetically similar to hippos, and that in general, fish swim in the water with their tails waging from side to side, while mammals swing their tails up and down. The reason for this is related to the changes in the vertebral structure of the tail of marine mammals, and it is difficult to compare the vertebral structure of mammals from side to side.

1. Mammalian marine animals have a complete mammalian skeletal structureThe spine of the whale is similar to that of a mammal, and it also has a pelvis, although the hind limbs have atrophied and become smaller, but the vertebral movement pattern is still the same as that of mammals. Its bone structure directly determines the difficulty of swinging left and right, and swinging up and down also determines the asymmetry of the range of movement, and it is necessary to change the posture of the body to balance the uniform force and achieve the balance effect, so the swimming movement of the whale is also a kind of varicose movement of the whole body. <>

Second, the advance efficiency of fish in the ocean is much higher than that of cetaceans, fish only need to swing their tails to overcome the resistance of the sea water, while whales need to carry out undulating movements throughout their bodies, in contrast, the efficiency of fish is much higher, and cetaceans do not have an advantage at all. The front half of the body of the fish does not need to move, and the tail part has no other limbs, which has nothing to do with the spine, and will directly crush the cetacean in terms of speed. Although whales are not explosive, their endurance is much better than that of fish.

3. The ancestors of cetaceans lived on landModern biology shows that the ancestors of whales were mammals that lived on land and evolved from mammals. Its skeletal structure is determined by genetic factors, which can only swing up and down, and is directly determined by objective factors and conditions.

The law of biological development determines that fish can only wag their tails left and right, while mammals can only wag their tails up and down, which is the evolution of a long biological evolutionary process. Both methods have their own unique characteristics, and fish are more flexible than marine mammals.

Compared to fish, mammals swimming in the water have a vertebral structure that allows them to swing their tails up and down, because their tails are horizontal, resulting in asymmetrical range of movement, making it difficult to swing from side to side.

The main reason for this is that the body structure is different, mammals have a backbone, and they have a pelvis, which leads to the fact that they cannot sway from side to side. So it can only swing up and down.

The structure of mammalian vertebrae is very different from that of fish, their vertebrae mainly move in an up-and-down direction, while the fish vertebrae oscillate from side to side. The bones in the tail are the caudal vertebrae, which are part of the spine and move in the same direction as the entire spine. So mammals have their tails swinging up and down, while fish have tails swinging from side to side.

Although they all swim in the water, there are some left and right tail swings, mainly because their main force point is the tail, and only in this way can they swim in the water and mammals, relying on their own hands, so they can only swing their tails up and down.

This has a lot to do with the body structure of the organism, and the position of the vertebrae will cause it to float up and down or from side to side.

Basically, a small fish swings its tail from side to side, and a large fish swings its tail up and down. The reason lies in the influence of gravity. Now I will analyze the two ways of swinging the tail from the perspective of mechanics and compare the efficiency of swimming. <>

1.——Mechanical analysis of the swimming mode of small fish with left and right tail swing.

The small fish swims in the water with its tail swinging from side to side with the following strength. It has its own gravity, the buoyancy of the water, the forward drag and thrust.

Swinging from side to side creates a vortex in the tail of the fish. As shown in the figure below, this vortex is the driving force for the fish to move forward. Obviously, for the fish to swim faster, the tail must swing more vigorously and the resulting whirlpools be more pronounced in order to gain more forward momentum.

2.Upper and lower tails of big fish – mechanical analysis of swimming patterns.

The swimming style of the big fish is to swing down to the tail with the following strength. Forces, like small fish, also include the four forces shown in the diagram.

There is no difference in the way the upper and lower tails swim, and the vortex created by the tail is as follows. Similarly, to swim faster, the tail must swing more powerfully.

3.The comparison of the two methods is <>

From the above analysis, we know that both big and small fish must rely on a strong tail swing if they want to achieve faster speed. The stronger the tail, the faster it swings and the greater the forward speed gained. But the way you swing your tail from left to right is not the same as the way you swing your tail from top to bottom.

Figure below. When the tail swings from side to side, it only needs to overcome the water resistance on both sides. When swinging your tail, you need to overcome the gravity of your tail. Due to their small size and weak strength, small fish have evolved to swing their tails from side to side to reduce the influence of their own gravity and achieve higher swimming efficiency.

For large fish, they are larger and more powerful. The way the tail swings up and down increases energy expenditure, but it has enough power. In addition, when swinging downward, you can also use your own gravity to evolve a more efficient swimming mode that swings up and down.

4.Fish biomimetic advances research.

Based on the way the fish parade, some scholars have developed swinging thrusters. Choose an airfoil structure with a tail that can swing. Using fluid mechanics software for analysis, the following figure is the model diagram before and after deformation. <>

As mentioned above, the evolution of the wake vortex system has a direct impact on the hydrodynamic properties of fish. It is of great significance to explore the swimming mechanism of fish by studying the non-constant flow field caused by the fluctuation and oscillation of the overall model of fish. Through the analysis, the tail vortices with different Straauhar numbers were obtained.

The Straubhar number is a parameter related to swing and speed. Through these studies, the most efficient swing and swimming speeds for propulsion were finally determined.

5.Summary. An important reason for swinging left and right and swinging up and down is the effect of gravity. Small fish have relatively little strength, and in order to save their energy, they will swing their tails from side to side. Big fish have a lot of strength. While they need to overcome a certain amount of gravity, the parade is more efficient.

The left and right tail swing is more efficient because the upper and lower tail swing back is affected by the earth's gravity, resulting in an uneven force. Moreover, the tail of mammals generally plays a stabilizing role, and the gravitational effect of the left and right tail swing has always been balanced. The tail of the fish is what provides forward momentum.

Swing the tail up and down. If you swing the tail left and right, it is exactly perpendicular to the resistance of the water, and the resistance is large, and if you swing the tail up and down, the resistance is smaller, so the efficiency of the tail swing up and down is high.

You can't use the tail swing method to judge which swim faster, because different swing methods achieve different effects, such as whales, mammals need to rely on the abdomen to develop breathing, and the tail swings up and down in order to better control the movement of the body up and down, and then be able to breathe. Fish that wag their tails from side to side can breathe freely in the water.

The body structure of ordinary fish is vertical, so it can only swing its tail from side to side, while mammalian fish have a large body and can swing their tail up and down, I think it is more efficient to swing their tail left and right, and the frequency of tail swing is faster and faster.

The difference between ordinary fish, which are also aquatic creatures, and mammals, such as whales, in the process of swimming, mainly depends on the developmental changes of the vertebrae during evolution。In fact, water mammals have the same skeletal structure as land mammals, but the hind limbs of water mammals gradually degenerate and shrink with changes in lifestyle, so in essence, water mammals still move in the same way as land animals. Therefore, it is difficult for them to swing from side to side like fish in the water, and they can only swing up and down according to the skeletal structure of the spine.

Not only that, the movement of mammals in the water when swinging their tails up and down is often asymmetrical, so it is easy to swim if they are not adjusted, so the water mammals such as whales often need to adjust their swimming posture to change the force in the water when they swing their tails up and down, and maintain balance when the upper and lower forces are applied to maintain the stability of the body. Then, despite trying to keep the body in balance, the whale's swimming in the water is also a flex motion.

Although fish have bones, but their structure and spine are completely different, they swing their tails left and right to overcome the resistance in the water and get forward power, so most of the fish only need to swing their tails in the process of swimming, and the first half of the body is almost in a state of no movement, so the swimming efficiency of the fish is higher, and the inconvenient control of the spine is removed, and the swimming speed of the fish in the water as a whole can "kill" the whale.

The whale is limited by the spine, and its undulating movement needs to mobilize the bones of the whole body to cooperate, because the ancestors of water mammals may be land creatures, so the posture of swimming in the water is still not as good as that of ordinary fish, which are the physiological structure basis of water mammals up and down and tail swinging.

Similarly, ordinary fish are not able to swing their tails up and down like whales, and they do not have the strength base to swing their tails up and down, so they can only get power by swinging their tails left and right.

Both of these methods of swinging have their own advantages, as well as their own flaws, which are selected according to the ancestors of the creatures and their living habits, and the fish species choose to swing their tails from side to side, because they must be more efficient and more agile, and sea creatures like whales, most of them are the masters of the sea, they basically have no enemies, so they do not need to move more efficiently and do not need to avoid enemies.

Because fish swing their tails from side to side to generate forward momentum, mammals swing their tails up and down to protect their balance.

Unlike the bone structure and breathing style of animals, fish do not need to go to the surface of the water if they use their gills to breathe, but mammals need to float up and down frequently to ventilate and then dive, and if they swing their tails up and down, they can move.

Common fish and mammals, represented by whales, are also aquatic creatures that have evolved mainly depending on the development and changes of the spine. In fact, mammals in the water have the skeletal structure of the spine and pelvis just like mammals on land, but the hind limbs of mammals in the water gradually degenerate and atrophy with changes in lifestyle. So, essentially, mammals still move in the same way as they do on land.

As a result, they have a hard time swinging from side to side like a fish in the water and can only swing up and down depending on the structure of the spine.

Fish wag their tails from side to side to reduce resistance to move in the water, while mammals are land creatures and swing their tails up and down to reduce air resistance.

Both of these swinging methods have their own advantages and their own disadvantages, which are determined according to the ancestors of the animal and their habits, and the fish choose to wag their tails from side to side because they need more speed and a more flexible body, while sea creatures like whalesThey are basically the overlords of the sea, they have few natural predators, so they don't need to move faster and don't need to run away from predators.

The structure of mammalian vertebrae is very different from that of fish, and their vertebrae move mainly in an up-down direction, while the spine of fish oscillates from side to side. The bones in the tail are the caudal vertebrae, which are part of the spine and move in the same direction as the entire spine. Therefore, mammals, including whales, mainly swing their tails up and down, while fish mainly swing their tails from side to side.

First, due to the structure of the body, their bone shapes are different. Second, the structural influence of the spine. The third oxygen supply is required, and mammals breathe by their lungs.

I think that fish swim in the water by swinging from side to side, while mammals float on the surface of the water and need to swing up and down.

The fish species in the water swing their tails from side to side, but the vast majority of mammalian species in the water are up and down with their tails, which is related to their ancestors, because dolphins and whales are all mammals evolved, and its tail swinging method is directly affected by changes in the spine. <>

The vast majority of fish species in the water are all tail swinging left and right, sprinters are very explosive, running very fast, but they do not have a lasting endurance, the vast majority of fish seen in the water are all of this kind of they are more to escape or feed on smaller creatures than themselves, so they must swim more quickly, suitable for a condition such as water, and then try to reduce the resistance, they have a faster efficiency to make themselves survive, Since their spine has nothing to do with other bodies, in other words, they only have their tails and no other bodies. <>

Dolphins and whales in the sea, most of their swimming methods are swaying up and down, because of the direct influence of their ancestors, their ancestors are on the ground, in other words, their ancestors have limbs, but they come to the water, the limbs slowly degenerate and the tail remains, but the tail swinging method is the same as his feet, he and the swing of the hand can not be completely consistent, if it is completely in the same direction, then it will happen like a crab walking, This is obviously not in line with the regularity of biological movement, so even when they come to the water, they are still this kind of up and down swing method, although this kind of up and down swing method is not too high, but they have a more durable endurance efficiency. <>

Both of these methods of swinging have their own advantages, as well as their own flaws, which are selected according to the ancestors of the creatures and their living habits, and the fish species choose to swing their tails from side to side, because they must be more efficient and more agile, and sea creatures like whales, most of them are the masters of the sea, they basically have no enemies, so they do not need to move more efficiently and do not need to avoid enemies.