Our goal was to assess regional differences in denticle density and skin tensile properties in four coastal species of shark. We hypothesized that the denticle density, tensile strength (MPa), stiffness (MPa), and toughness of skin (MJ·m^-3) would vary regionally along the body of an individual and among species. An hourglass-shaped punch was used to extract the skin samples at 10 anatomical landmarks and denticle density was quantified. Denticle density varied significantly among both regions and species, and showed a significant species by region interaction. Skin samples were tested in tension at a strain rate of 2 mm-s until failure. We found significant species and region effects for all tensile and denticle density properties. Also, denticle density increases with skin stiffness but decreases with toughness. Shark skin toughness is similar to that of mammalian tendons. These data show shark skin functions as an exotendon, able to conserve energy during swimming. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

The hydrodynamics of three different shark heads: Eusphyra blochii (Winghead shark), Carcharhinus acronotus (Blacknose shark) and Sphyrna tiburo (Bonnethead shark) were investigated. Force transducer measurement was used to explore how the cephalofoil (wing-shaped head) affects maneuverability and efficiency. As the dynamic behavior of maneuvering wings differs from that of the steady state motion, experiments have been conducted to simulate: 1) steady-state (no yaw motion) constant velocity swimming, 2) constant forward velocity with yawing motion of the head and 3) turning maneuvers. Different range of velocities, angle of attack, yaw frequency and yaw amplitude were tested. Drag and lift coefficients were calculated and compared. The lift coefficient of Winghead shark is much higher compared to the other sharks. The lift-to-drag ratio showed that the Winghead shark has a hydrodynamic advantage compared to Blacknose shark and Bonnethead shark. / by Julien Barousse. / Thesis (M.S.C.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.