Difference Between Flippers & Fins

The word fin was first used to describe the limbs of fish, but has grown to categorize other animal limbs as well. While fins and flippers are often wrongly used interchangably, there are differences between fins and flippers on a marine animal.

  1. Purpose

    • Fins are a a membranous appendage responsible for steering or balancing the animal's body in water. Flippers evolved from legs, becoming flat broad limbs specialized for an aquatic animal's swimming up, down, back and forth.

    Number

    • The number of fins a marine animal has varies depending on the species, but fins can be found on the side of the animal, on top and bottom; also called dorsal, and in the lower back, called the caudal fins. Flipper amounts range depending on the animal; penguins have a single flipper at the end of their body, while sea turtles have two back flippers, and dolphins have two, front flipper limbs.

    Bones

    • Fins are made from either connective tissue or fragile bony spines protruding from the body. The bony spines in fins are held together in a webbed fashion. Flippers however, contain bones similar to a human hand with cartilage and connective tissue surrounding the bones in a thicker manor.