What Are the Functions of Dorsal Fins?

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Dorsal fins enable sharks and fish to remain upright as they swim through the water. These fins are vertical and help sharks and fish to balance as they move. In both animals, dorsal fins are located along the spine; most fish have just one dorsal fin, while sharks generally have two.

Dorsal fins, in addition to allowing fish and sharks to swim, have had their fair share of fame in the media. These fins are the first to appear when sharks rise from the water and are featured in films such as Jaws. Dorsal fins are often triangular in shape; they are wide and broad and quite flexible with short rear tips and sturdy muscular bases. Their build makes them suitable for stabilization, proving especially helpful for sharks and fish swimming through currents and strong waves. The flexible composition of dorsal fins allows fish and sharks to have some control over their movements; as pilots can manipulate landing gear on airplanes, sharks and fish can bend and retract their dorsal fins when less stabilization is necessary then unfurl them when necessary for navigating through treacherous waters or engaging in high-speed pursuits after potential prey. The smaller, secondary dorsal fins on sharks facilitate traveling at high speeds by reducing drag.