Cuttlefish have a unique physical feature called a "fin" or "mantle" that allows them to swim. The mantle is a broad, undulating structure that runs along the sides of the cuttlefish's body. By rhythmically contracting and relaxing this fin, cuttlefish can propel themselves through the water with a smooth, gliding motion.
In addition to the fin, cuttlefish can also use a specialized organ called the "siphon" to maneuver. The siphon can expel jets of water, allowing the cuttlefish to change direction quickly, move backward, or accelerate rapidly. This jet propulsion mechanism is helpful for swift movements, evasion, and hunting.
Together, the mantle fin and siphon give cuttlefish their remarkable swimming abilities, allowing them to navigate their marine environments with agility and control.