Why do crabs walk sideways?
Quick Answer
Most crabs walk sideways because their legs bend outward at the joints, so moving to the side is the fastest and most efficient direction.
The Full Story
A crab's legs are attached along the sides of a wide, flat body, and the joints mainly flex outward rather than forward and back. Stepping sideways lets the legs move without tripping over one another, allowing quick, stable movement. Sideways scuttling also lets crabs dash into burrows or crevices while keeping their claws facing a threat. Not all crabs walk sideways: some, such as spider crabs and frog crabs, can walk forwards. The soldier crab of Australia is also known for walking forwards.
Key Facts
YouTube Angle
Suggested video title for this topic:
"Watch a crab's leg joints in slow motion and the sideways shuffle suddenly makes sense."