title: Bending rules for animal propulsion.
abstract: Animal propulsors such as wings and fins bend during motion and these bending patterns are believed to contribute to the high efficiency of animal movements compared with those of man-made designs. However, efforts to implement flexible designs have been met with contradictory performance results. Consequently, there is no clear understanding of the role played by propulsor flexibility or, more fundamentally, how flexible propulsors should be designed for optimal performance. Here we demonstrate that during steady-state motion by a wide range of animals, from fruit flies to humpback whales, operating in either air or water, natural propulsors bend in similar ways within a highly predictable range of characteristic motions. By providing empirical design criteria derived from natural propulsors that have convergently arrived at a limited design space, these results provide a new framework from which to understand and design flexible propulsors.
authors.affiliation: 1] Biology and Environmental Sciences, Roger Williams University, Bristol, Rhode Island 02809, USA [2].
authors.forename: Kelsey N
authors.initials: KN
authors.lastname: Lucas
authors.affiliation: 1] Biology, Providence College, Providence, Rhode Island 02918, USA [2].
authors.forename: Nathan
authors.initials: N
authors.lastname: Johnson
authors.affiliation: Department of Biology, Indiana University, Bloomington, Indiana 47405, USA.
authors.forename: Wesley T
authors.initials: WT
authors.lastname: Beaulieu
authors.affiliation: Biology, Providence College, Providence, Rhode Island 02918, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Cathcart
authors.affiliation: Biology, Providence College, Providence, Rhode Island 02918, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Tirrell
authors.affiliation: 1] Biology and Environmental Sciences, Roger Williams University, Bristol, Rhode Island 02809, USA [2] Whitman Center, Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA.
authors.forename: Sean P
authors.initials: SP
authors.lastname: Colin
authors.affiliation: 1] Biology, Providence College, Providence, Rhode Island 02918, USA [2] Whitman Center, Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA.
authors.forename: Brad J
authors.initials: BJ
authors.lastname: Gemmell
authors.affiliation: Graduate Aeronautical Laboratories and Bioengineering, California Institute of Technology Pasadena, California 91125, USA.
authors.forename: John O
authors.initials: JO
authors.lastname: Dabiri
authors.affiliation: 1] Biology, Providence College, Providence, Rhode Island 02918, USA [2] Whitman Center, Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA.
authors.forename: John H
authors.initials: JH
authors.lastname: Costello
mesh_terms: D058500:Animal Fins / Q000502:physiology*; D000818:Animals; D005426:Flight, Animal / Q000502:physiology*; D007313:Insecta / Q000502:physiology; D008974:Mollusca / Q000502:physiology; D010802:Phylogeny; D013550:Swimming / Q000502:physiology*; D014714:Vertebrates / Q000502:physiology*; D014921:Wings, Animal / Q000502:physiology*