[DoctorBeaver (OP)]

Advantageous characteristics evolve, disadvantageous ones die out. So what advantage does walking sideways give crabs? How did that evolve?

And are there any other animals that perambulate in such a manner?

[JimBob]

Do you remember the song "crabs walk sideways and lobsters walk straight ... ?"

Both are crustaceans, and there is a huge number of shrimp that also walk straight so I doubt there is much advantage. But the only advantage I can think of is the surprise it gives to predators that normally pray on "straight" walking critters.

[DoctorBeaver (OP)]

That's better than anything I can think of.

[paul.fr]

I refer the honerable gentleman, to a question previously aske.
http://www.thenakedscientists.com/forum/index.php?topic=6635.0

[DoctorBeaver (OP)]

Thanks Paul, I hadn't seen that thread; or, at least, I don't remember having seen it. It explains the mechanics but not the why.

[paul.fr]

Thanks Paul, I hadn't seen that thread; or, at least, I don't remember having seen it. It explains the mechanics but not the why.

if only i knew why, the story of my life...why, why why