RT Journal Article
SR Electronic
T1 Scaling of swimming performance in baleen whales
JF The Journal of Experimental Biology
JO J. Exp. Biol.
FD The Company of Biologists Ltd
SP jeb204172
DO 10.1242/jeb.204172
VO 222
IS 20
A1 Gough, William T.
A1 Segre, Paolo S.
A1 Bierlich, K. C.
A1 Cade, David E.
A1 Potvin, Jean
A1 Fish, Frank E.
A1 Dale, Julian
A1 di Clemente, Jacopo
A1 Friedlaender, Ari S.
A1 Johnston, David W.
A1 Kahane-Rapport, Shirel R.
A1 Kennedy, John
A1 Long, John H.
A1 Oudejans, Machiel
A1 Penry, Gwenith
A1 Savoca, Matthew S.
A1 Simon, Malene
A1 Videsen, Simone K. A.
A1 Visser, Fleur
A1 Wiley, David N.
A1 Goldbogen, Jeremy A.
YR 2019
UL http://jeb.biologists.org/content/222/20/jeb204172.abstract
AB 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.