![]() ![]() ![]() The tubercles break up the passage of water, maintaining even channels of the fast-moving water, limiting turbulence and providing greater maneuverability. The whale's surprising dexterity is due primarily to its non-conventional flippers, which have large, irregular looking bumps called tubercles across their leading edges. įlippers on humpback whales ( Megaptera novaeangliae) have non-smooth leading edges, yet demonstrate superior fluid dynamics to the characteristically smooth leading edges of artificial wings, turbines and other kinds of blades. Breaking up channels of fast-moving water allows humpbacks to retain their "grip" on the water, and turn at sharper angles even at low velocities. The tubercles on the flippers of humpback whales improve the hydrodynamics of the flipper at their size. Flippers are one of the principal control surfaces of cetaceans (whales, dolphins and porpoises) due to their position in front of the center of mass, and their mobility which provides three degrees of freedom. Hydrodynamics Ĭetacean flippers may be viewed as being analogous to modern engineered hydrofoils, which have hydrodynamic properties: lift coefficient, drag coefficient and efficiency. ![]() The flippers of penguins became thicker, denser and smaller while being modified for hydrodynamic properties. Form constrains function, and the wings of diving flying species, such as the murre or cormorant have not developed into flippers. ![]() The evolution of flippers in penguins was at the expense of their flying capabilities, in spite of evolving from an auk-like ancestor that could 'fly' underwater as well in the air. In cetaceans, they are primarily used for control while the fluke is used for propulsion. Flippers are used for different types of propulsion, control, and rotation. Locomotion įor all species of aquatic vertebrates, swimming performance depends upon the animal's control surfaces, which include flippers, flukes and fins. Swimming appendages with the digits still apparent, as in the webbed forefeet of amphibious turtles and platypus, are considered paddles rather than flippers. Some flippers are very efficient hydrofoils, analogous to wings ( airfoils), used to propel and maneuver through the water with great speed and maneuverability (see Foil). The dorsal structure on cetaceans is called the "dorsal fin" and the large cetacean tails are referred to primarily as flukes but occasionally as "caudal fins" neither of these structures are flippers. Tetrapod limbs which have evolved into fin-like structures are usually (but not always) called "flippers" rather than fins. However, the hydrodynamic control surfaces of fish are always referred to as "fins" and never "flippers". Usage of the terms "fin" and "flipper" is sometimes inconsistent, even in the scientific literature. manatees and dugongs), and marine reptiles such as the sea turtles and the now-extinct plesiosaurs, mosasaurs, ichthyosaurs, and metriorhynchids. walruses, earless and eared seals), sirenians (e.g. Īnimals with flippers include penguins (whose flippers are also called wings), cetaceans (e.g. In animals with four flippers, such as pinnipeds and sea turtles, one may distinguish fore- and hind-flippers, or pectoral flippers and pelvic flippers. In animals with two flippers, such as whales, the flipper refers solely to the forelimbs. It refers to the fully webbed, swimming appendages of aquatic vertebrates that are not fish. This green turtle is about to break the surface for air at Kona, Hawaii.Ī flipper is a broad, flattened limb adapted for aquatic locomotion. ![]()
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