Efficient Propulsion System

Biological Strategy

Yellowfin tuna

AskNature Team

Image: James Thornton / Unsplash / CC BY SA - Creative Commons Attribution + ShareAlike

Move in/on Liquids

Water is not only the most abundant liquid on earth, but it’s vital to life–so it’s no surprise that the majority of life has evolved to thrive on and under its surface. Moving efficiently in and on this dense and dynamic substance presents unique challenges and opportunities for living systems. As a result, they have evolved countless solutions to optimize drag, utilize surface tension, fine tune buoyancy, and take advantage of various types of currents and fluid dynamics. For example, sharks can slide through water by reducing drag due to their streamlined shape and specially shaped features on their skin.

Search this Function

Fish

Class Agnatha (“without jaws”), Class Chondrichthyes (“cartilage fish”), Superclass Osteichthyes (“bone fish”): Sharks, eels, snapper, hagfish

The fish are a diverse group, comprising multiple classes within Phylum Animalia. The most well-known classes are Chondrichthyes, which has sharks and rays, and superclass Osteichthyes, which has all bony fish like cod and tuna. Unlike other vertebrates, fish only live in water. They use special adaptations like fins, gills, and swim bladders to survive. Most are ectothermic, meaning their body temperature depends on the water temperature around them. Over half of all vertebrates are fish. They’re found from the bottom of the sea to high mountain lakes.

Search this Living System

Tails of yellowfin tuna conserve energy by using thunniform swimming.

Some ocean-dwelling fish, including tuna, mackerel, and sharks, have a form of swimming called thunniform. In thunniform swimming, most of the lateral movement occurs in the tail and adjacent area of the body with very little bending of the fish’s body. The tail or caudal fin is usually large and crescent shaped to increase the power of each sweeping motion. This form of swimming is ideal for species that cover long distances and swim fast because it conserves energy.

Related Innovation

Innovation: Industry

Unmanned Underwater Vehicle Inspired by Tuna

Boston Engineering

The BIOSwimmer from Boston Engineering is a highly maneuverable UUV designed to work in harsh and hard-to-reach environments.

Last Updated October 23, 2016

References

Journal article

The Chemical Works of Faraday in Relation to Modern Science

Sci Am | 10/06/2015 | Dewar

embedly preview

Reference

“Yellowfin tuna (Thunnus albacares) swimming kinematics was studied in a large water tunnel at controlled swimming velocities (U). Quantified kinematic variables included the tail-beat frequency, stride length (l), caudal amplitude, yaw, the propulsive wavelength, the speed of the propulsive wave (C) and the sweepback angle of the pectoral fins. In general, all variables, except the propulsive wavelength and consequently C, are comparable to values determined for other teleosts. The propulsive wavelength for the tunas (1.23–1.29L, where L is fork length) is 30–60 % longer than in other cruise-adapted teleosts such as salmonids. The resulting thunniform swimming mode and the morphological and anatomical adaptations associated with the long propulsive wavelength (e.g. fusiform body shape, rigid vertebral column) act to minimize anterior resistance and maximize caudal thrust. The long propulsive wavelength also increases the maximum l which, in concert with the elevated muscle temperatures of tunas, increases their maximum swimming velocity.” (Dewar and Graham 1994:45)

Journal article

Studies of tropical tuna swimming performance in a large water tunnel--III Kinematics

Dewar H; Graham JB

embedly preview

AskNature