Crabs are a kind of animal that we are familiar with. They often stay in the water, but we sometimes see them move on land.When we observe them walking, we will find that they seem to walk sideways, and their movements are more interesting.Indeed, most crabs walk in this way, walking sideways, not directly forward.However, not all crab species walk like this.There are many kinds of crabs, with some exceptions.For example, hermit crabs, short finger crabs and monk crabs can go straight forward, just like other animals.
As mentioned above, most crabs walk sideways, and their special way of moving has a lot to do with their body structure.The main reason is that the structure of the crab's foot is very special.The crab's foot refers to the foot that the crab uses to walk, which is composed of seven joints, and the way these joints move is up and down, so the crab walks horizontally when it moves.
In addition, the crab walking sideways also has a lot to do with the contrast between the left and right chest and the front and back span.Crabs have legs on either side of the body, and their thorax spans more from side to side than from front to back, which means they are wider than they are long.Therefore, when they are active, they can only use one side of the foot to bend and grasp the ground tightly; At this point, the other side of the foot can be extended outward, and then when it touches the ground, it will shrink.At this time, the original curved side of the foot will be straightened, it seems that the crab is walking sideways.
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