Fin
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A fin is a thin appendage or component attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while t
Fish get thrust moving vertical tail fins from side to side.
Cetaceans get thrust moving horizontal tail fins up and down.
Stingrays get thrust from large pectoral fins.
Ship propeller
Dorsal fin
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A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the f
Fin
…other aquatic animals, such as cetaceans, actively propel and steer themselves with pectoral and tail fins. As they swim, they use other fins, such as dorsal and anal fins, to achieve stability and refine their maneuvering. The fins on the tails of cetaceans, ichthyosaurs, metriorhynchids, mosasaurs and…
Dorsal fin of a shark
Most fish, like this large goldfish, have one dorsal fin.
Many catfish can lock their dorsal fin spines erect and secrete venom to discourage predators.
The great white shark's dorsal fin contains stabilizing dermal fibers that stiffen dynamically as it swims faster to control roll and yaw.