Do All Crabs Walk Sideways?
If you’ve ever seen crabs moving along the shoreline, you’ve probably noticed that they move differently than human beings. Instead of walking forward on two legs, they move quickly sideways in a flurry with their multiple legs.
Crabs move sideways for the same reason humans move forward: that’s how their bodies were built to move. Human beings have knees that bend forward. Therefore, it’s only natural that we would move forward with each step we take.
Crabs, on the other hand, have multiple legs and they’re located on the sides of their bodies. In addition, their leg joints bend outward. Given this particular design of their bodies, it’s most efficient and natural for crabs to move sideways.
Not all crabs move sideways, however. There are a few species of crabs that can move forward, because their bodies are shaped in a way that makes them longer than they are wide. Examples of these crabs include raninids, Libinia emarginata, and Mictyris platycheles.
In addition, most crabs have a front pair of legs that are mainly used for defense and grasping food. These front legs can be used to move forward, but doing so is not very efficient and doesn’t allow the crab to move quickly. Thus, most crabs move sideways since they can move quickly and most efficiently that way.