Organismic and Evolutionary Biology, Harvard University, Museum of Comparative Zoology, Cambridge, MA 02138, USA.
Department of Biology, West Chester University, West Chester, PA 19383, USA.
Biol Lett. 2019 Jul 26;15(7):20190103. doi: 10.1098/rsbl.2019.0103. Epub 2019 Jul 17.
Dolphin skin has long been an inspiration for research on drag reduction mechanisms due to the presence of skin ridges that could reduce fluid resistance. We gathered in vivo three-dimensional surface data on the skin from five species of odontocetes to quantitatively examine skin texture, including the presence and size of ridges. We used these data to calculate k values, which relate surface geometry to changes in boundary layer flow. Our results showed that while ridge size differs among species, odontocete skin was surprisingly smooth compared to the skin of other swimmers (average roughness = 5.3 µm). In addition, the presence of ridges was variable among individuals of the same species. We predict that odontocete skin ridges do not alter boundary layer flows at cruising swimming speeds. By combining k values and morphological data, our work provides evidence that skin ridges are unlikely to be an adaptation for drag reduction and that odontocete skin is exceptionally smooth compared to other pelagic swimmers.
海豚皮因其表面的脊状结构而长期以来一直是减少阻力机制的研究灵感来源，这些脊状结构可以减少流体阻力。我们从五种齿鲸身上采集了活体三维皮肤表面数据，以定量检查皮肤纹理，包括脊的存在和大小。我们使用这些数据计算了 k 值，该值将表面几何形状与边界层流的变化联系起来。我们的结果表明，尽管脊的大小在物种之间存在差异，但与其他游泳者（平均粗糙度= 5.3 µm）相比，齿鲸的皮肤出奇地光滑。此外，同一物种的个体之间脊的存在也存在差异。我们预测，齿鲸皮肤的脊不会改变巡游游泳速度下的边界层流。通过结合 k 值和形态数据，我们的工作提供了证据表明，皮肤脊不太可能是减少阻力的适应，与其他远洋游泳者相比，齿鲸的皮肤异常光滑。
