Clams are known to be very sensitive and only open their shells slightly in order to feed
Apparently, the mollusks first undergo an acclimatization process after being caught and brought to the laboratory. It takes about two weeks. During that time, scientists also determine the natural opening of their shell—clams leave a slight opening and feed by filtrating water. Within one hour, one clam can filter and thus analyze the quality of 1.5 liters of water. They live only in completely clean waters and shut their shells immediately if they sense any impurity.