Many people mistakenly believe that mussels stay in one place for their entire lives. But if conditions aren't favorable, mussels will pack it up and move to find a better area. For deep-sea mussels, this is an important ability to have if the vent you and your bacteria are depending on slowly stops flowing.
How do mussels move?—by using their muscles. More specifically, they extend their muscular foot outside their shells to pull themselves forward. It is believed that they can use their byssal threads as small ropes to pull themselves forward, too.
This video clip was created from a series of photographs taken over a period of almost two days on the seafloor. Notice how some of the mussels move by extending their white foot outside their shells. They may never win any races, but being able to move even a short distance to find better conditions can mean the difference between life and death for a mussel.