these clams will siphon water all day and when they spit, they are getting rid of waste. when they siphon the water, they collect nitrates and use them for food. if you are even in doubt that your clam is alive, just pick it up and lightly try to pry it open, if it is locked shut, still alive and good to go! if they bury themselves in the sand, it's only because they want to, it's really cool how they do it too. Thanks for the tip on the supermarket clams.... i hope swf.com doesn't get too mad!