Giant Clam (speckled green color) rests in the Ulong Channel.  A clam this size can be 200 years old.  It's about 4' across.   &quot;Clams feed on plankton by filter feeding. Clams filter feed by drawing in water containing food using an incurrent siphon. The food is then filtered out of the water by the gills and swept toward the mouth on a layer of mucus. The water is then expelled from the animal by an excurrent siphon.&quot; [Wikipedia.]