I finally took the time to make a video of the clam that I have (which is not like the one you guys have, but rather the type of clam that you would eat) moving itself around with its foot. It takes it a long time to start moving after I unbury it, but one it does, it is actually pretty quick at turning around and digging into the sand. My kids had told me that I should draw some eyes on it so that when it sticks out its 'tongue' it would look like it was smiling! Obviously they are easily amused, but I never thought of that so it at least proves that they have a good imagination!
http://s96.photobucket.com/albums/l1...rrent=Clam.flv