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- Mar 8, 2004
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cuttlegirl said:But maybe since the ancestral cephalopod only moved in two dimensions, it didn't need 8 appendages. Modern cephalopods navigate three dimensional space.
That's true, but when octos are using their arms for locomotion, they're mostly in contact with the bottom or with whatever rock/cave/reef they're involved with, so they're not really any more 3-d than squirrels or monkeys. Of course, octos can free-swim, too, but they don't use their arms most of the time when they're doing, that-- and squids, who spend their whole lives in the 3-d world, don't use their arms and tentacles for locomotion at all... and they have ten limbs!
Also, most snails can only crawl forward, they can turn and move another direction, but it is still head forward.
wow! I had no idea (although I guess I've never thought about it before.) So if a snail goes into a little box canyon sort of place, the only way it can get out is to crawl up the walls, I guess.