question about the reasons of such a method of movement of crabs, as well as about why cancers draw back, held the people in ancient times.Born even a legend like a crab, and cancer is accompanied by Sea King for a walk, and when meeting with a shark cancer, scared, he jumped back, and walked sideways crab in the coming seagrass beds.Sea King punished the two subjects of cowardice, forcing one to back away all life, and the other - to go sideways.

Of course, the modern man is not satisfied with such a fabulous explanation.

Anatomy crab

Crabs have a very long and powerful legs that some are turned forward.Due to this the joints can not rise above the abdomen.It is very important for the animal, conducting most of their time in shallow water and has a lot of natural enemies.In case of danger, the crab is easily spread on the sandy bottom, without attracting attention, and quickly hide under rocks.

But like structure crab legs have to pay so that the highest speed it can develop when moving sideways.When the speed is not critical, the crab can walk in any direction, but sensing danger, he seeks to escape and begins to move the most convenient way.Monitor source of danger that does not stop, because his eyes are on stalked outgrowths, creating all-round visibility.

There is another reason to move sideways in the event of danger.Claws of the crab, as well as human hands, asymmetric - this is easy to see by looking at him, one of the other larger claws.Like humans, leading in most individuals is the right claw, crab grabs her food, and when he left to protect.Running away from someone dangerous, it is covered by a "defensive" claw, but it is also more convenient to do, moving sideways.

Cancer backtracking

interesting feature of the movement, and there is a close "relative" crab - the crayfish.This animal is swimming tail first, because it is in such a direction the body of cancer has the most streamlined shape, and motion in the opposite direction would prevent large claws.

cancer can walk in any direction, but the maximum speed develops when moving backwards.The tail while bent under the abdomen and emits a stream of water, which is "working" on the principle of a jet engine, increasing the speed of movement of the animal.

not always crab walks sideways and moves back the cancer - the two do so only in an emergency.The meeting with a man animals perceive as a threat, so people often observe is a movement of crabs and crayfish.