Cnidarians, which include animals like jellyfish, corals, and sea anemones, have a unique way of moving through their aquatic environments. The primary method of movement among most cnidarians is through a process called pulsation.
Many jellyfish, for example, use a simple form of locomotion known as passive drifting interspersed with active pulsations. When a jellyfish contracts its bell, it expels water, allowing it to propel upward and then drift back down as the bell relaxes. This rhythmic contraction and expansion enable jellyfish to move in search of food or to escape from predators.
Corals and anemones, on the other hand, are typically anchored to the substrate and do not exhibit movement in the same way. Instead, they can retract their tentacles or their entire body part into their base for protection or to capture prey. Some species can slowly inch along the seafloor by gliding on their base or using their tentacles.
So, while cnidarians might not swim or walk like other animals, their unique methods of pulsation and retraction allow them to navigate, feed, and protect themselves in their aquatic habitats.