Scaling of swimming performance in baleen whales.

Published

Journal Article

The scale dependence of locomotor factors has long been studied in comparative biomechanics, but remains poorly understood for animals at the upper extremes of body size. Rorqual baleen whales include the largest animals, but we lack basic kinematic data about their movements and behavior below the ocean surface. Here, we combined morphometrics from aerial drone photogrammetry, whale-borne inertial sensing tag data and hydrodynamic modeling to study the locomotion of five rorqual species. We quantified changes in tail oscillatory frequency and cruising speed for individual whales spanning a threefold variation in body length, corresponding to an order of magnitude variation in estimated body mass. Our results showed that oscillatory frequency decreases with body length (∝length-0.53) while cruising speed remains roughly invariant (∝length0.08) at 2 m s-1 We compared these measured results for oscillatory frequency against simplified models of an oscillating cantilever beam (∝length-1) and an optimized oscillating Strouhal vortex generator (∝length-1). The difference between our length-scaling exponent and the simplified models suggests that animals are often swimming non-optimally in order to feed or perform other routine behaviors. Cruising speed aligned more closely with an estimate of the optimal speed required to minimize the energetic cost of swimming (∝length0.07). Our results are among the first to elucidate the relationships between both oscillatory frequency and cruising speed and body size for free-swimming animals at the largest scale.

Full Text

Duke Authors

Cited Authors

  • Gough, WT; Segre, PS; Bierlich, KC; Cade, DE; Potvin, J; Fish, FE; Dale, J; di Clemente, J; Friedlaender, AS; Johnston, DW; Kahane-Rapport, SR; Kennedy, J; Long, JH; Oudejans, M; Penry, G; Savoca, MS; Simon, M; Videsen, SKA; Visser, F; Wiley, DN; Goldbogen, JA

Published Date

  • October 23, 2019

Published In

Volume / Issue

  • 222 / Pt 20

PubMed ID

  • 31558588

Pubmed Central ID

  • 31558588

Electronic International Standard Serial Number (EISSN)

  • 1477-9145

International Standard Serial Number (ISSN)

  • 0022-0949

Digital Object Identifier (DOI)

  • 10.1242/jeb.204172

Language

  • eng