Scaling of swimming performance in baleen whales
Scaling of swimming performance in baleen whales
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DOI：
10.1242/jeb.204172
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发表时间：
2019-10-01
影响因子：
2.8
通讯作者：
Goldbogen, Jeremy A.
中科院分区：
文献类型：
--
作者：
Gough, William T.;Segre, Paolo S.;Goldbogen, Jeremy A.
在比较生物力学中，运动因子的尺度依赖性已经被研究了很长时间，但对于处于身体尺寸上限的动物来说，我们仍然知之甚少。须鲸是最大的动物之一，但我们缺乏关于它们在海面下运动和行为的基本运动学数据。在这里，我们结合了空中无人机摄影测量的形态测量学、鲸载惯性传感标签数据和流体动力学建模来研究五种常见物种的运动。我们量化了个体鲸鱼的尾巴振荡频率和巡航速度的变化，这些变化跨越了三倍的体长变化，对应于估计体重的一个数量级变化。我们的研究结果表明，在2 m s（-1）时，振荡频率随体长（与体长（-0.5）成正比）而降低(3)，而巡航速度大致保持不变（与体长（0.08）成正比）。我们将这些振荡频率的测量结果与振荡悬臂梁（与长度（-1）成正比）和优化的振荡斯特劳哈尔涡旋发生器（与长度（-1）成正比）的简化模型进行了比较。我们的长度缩放指数与简化模型之间的差异表明，动物经常为了觅食或执行其他常规行为而非最佳地游泳。巡航速度与使游泳能量消耗最小化所需的最佳速度（与长度（-1）成正比）更接近。我们的研究结果是第一个阐明振荡频率、巡航速度和最大尺度自由游泳动物体型之间关系的研究。
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 (proportional to length(-0.5)(3)) while cruising speed remains roughly invariant (proportional to length(0.08)) at 2 m s(-1). We compared these measured results for oscillatory frequency against simplified models of an oscillating cantilever beam (proportional to length(-1)) and an optimized oscillating Strouhal vortex generator (proportional to 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 (proportional to length(-1)). 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.