Barton Kira

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Last Name
Barton
First Name
Kira
ORCID
0000-0003-1047-8078

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  • Article
    Tag-based estimates of bottlenose dolphin swimming behavior and energetics
    (The Company of Biologists, 2022-11-30) Gabaldon, Joaquin T ; Zhang, Ding ; Rocho-Levine, Julie ; Moore, Michael J ; van der Hoop, Julie ; Barton, Kira ; Shorter, K Alex
    Current estimates of marine mammal hydrodynamic forces tend to be made using camera-based kinematic data for a limited number of fluke strokes during a prescribed swimming task. In contrast, biologging tag data yield kinematic measurements from thousands of strokes, enabling new insights into swimming behavior and mechanics. However, there have been limited tag-based estimates of mechanical work and power. In this work, we investigated bottlenose dolphin (Tursiops truncatus) swimming behavior using tag-measured kinematics and a hydrodynamic model to estimate propulsive power, work and cost of transport. Movement data were collected from six animals during prescribed straight-line swimming trials to investigate swimming mechanics over a range of sustained speeds (1.9-6.1 m s-1). Propulsive power ranged from 66 W to 3.8 kW over 282 total trials. During the lap trials, the dolphins swam at depths that mitigated wave drag, reducing overall drag throughout these mid- to high-speed tasks. Data were also collected from four individuals during undirected daytime (08:30-18:00 h) swimming to examine how self-selected movement strategies are used to modulate energetic efficiency and effort. Overall, self-selected swimming speeds (individual means ranging from 1.0 to 1.96 m s-1) tended to minimize cost of transport, and were on the lower range of animal-preferred speeds reported in literature. The results indicate that these dolphins moderate propulsive effort and efficiency through a combination of speed and depth regulation. This work provides new insights into dolphin swimming behavior in both prescribed tasks and self-selected swimming, and presents a path forward for continuous estimates of mechanical work and power from wild animals.
  • Article
    In vivo viscoelastic properties of cetacean integument: an experimental characterization
    (Wiley, 2024-07-05) Yang, Dory Y. ; Shorter, K. Alex ; Moore, Michael J. ; Rocho-Levine, Julie ; Wells, Randall S. ; Barton, Kira ; Johnson, Mark
    Suction cups are commonly used to attach biologging tags to cetaceans, and interact mechanically with compliant integument, an organ primarily composed of skin and blubber. However, the impact of compliance on suction cup performance is difficult to predict because knowledge about in vivo integument mechanics is lacking. Here, an experimental approach is used to investigate the mechanical properties of common bottlenose dolphin (Tursiops truncatus) integument using a custom instrument, the static suction cup (SSCup), to collect data from both trained dolphins and wild individuals (n = 17) during a static pose. Three loading profiles were applied at three sites to quantify nonlinear stiffness, hysteresis, and creep. The site at the dorsal fin insertion exhibited the highest stiffness, while sites posterior to the blowhole and above the pectoral fin showed greater energy dissipation during cyclic loading. Viscoelastic behavior was observed across all sites. Suction cup performance on a surrogate material with broadly similar compliance showed reduced performance compared to cups on rigid acrylic: the maximum applied force at detachment on acrylic (50 N) was twice as large as the compliant substrate (25 N). Site-dependent compliance of integument may lead to varying performance of suction cups as an attachment method for tags.