Why do crabs walk sideways_ The secret of crabs

Among many animals, crabs are the most “domineering”, because others walk along, and only crabs are “walking sideways”. Many people can’t help asking why crabs walk sideways. Some people say that they are willful with pliers (money). This is just a joke. Let’s learn more about the reason why crabs walk sideways.

螃蟹为什么横着走路,螃蟹横行的秘密

There are several reliable statements about crabs walking sideways:
The first is about the earth’s magnetic field

螃蟹为什么横着走路,螃蟹横行的秘密

We know that crabs rely on the geomagnetic field to judge the direction of walking. In the long process of the formation of the earth, they have exchanged the north and south poles for many times, that is, the “N-S” poles exchange positions, which makes it difficult for many organisms to adapt and become extinct. Crabs are an ancient migratory animal. Its inner ear has small directional magnets and is very sensitive to geomagnetism. Due to the reversal of the geomagnetic field, the small magnet in the crab loses its original orientation. In order to survive in the reversal of the geomagnetic field, crabs adopt the practice of “responding to changes with invariance”. They simply do not move forward or backward, but walk horizontally. In this way, crabs can survive normally no matter how the north and south poles of the magnetic field change.

Second, from a biological point of view
The head and chest of a crab are indistinguishable in appearance, so they are called head and chest. Ten feet are on both sides of the body. The first pair of pincers are both tools for digging holes and weapons for defense and attack. The other four pairs of feet are used for walking, which is called walking feet. Each foot consists of seven sections, and the joints can only move up and down. For example, just like people, it’s a truth that elbows can’t turn out and knees can’t bend back. In fact, crabs can also walk slowly forward, but their stride, speed and efficiency are far lower than those walking horizontally.

螃蟹为什么横着走路,螃蟹横行的秘密

If you catch a crab and shake it hard with your hands, you will see that its eight legs swing left and right, but if you want to shake back and forth, you will find that the shaking range is very small. If you try harder, it is likely to break off with a “snap”.
Third, from the aspect ratio
The body width of a crab is longer than the length of its head and tail. The whole body is in a wide and flat shape. Walking sideways will be faster and save more energy. Moreover, if you enter the cave, walking sideways will be more convenient.

螃蟹为什么横着走路,螃蟹横行的秘密

Of course, not all crabs walk horizontally. For example, monk crabs can run forward. There are other crabs, such as hermit crabs. Many spider crabs living in seaweed can also climb vertically on seaweed.

Related Post