And so terrestrial organisms, like my cute dog Kieran, might be leaving footprints behind in dirt or in sand, but marine organisms leave footprints in the form of what we call wake structures, or hydrodynamic signatures, in fluid.

陆地上的动物们， 像我可爱的狗狗珂润，可能会在泥地或者沙地上留下脚印，但海洋生物的脚印，据其形态， 我们叫它尾流结构，或者水动力结构，这被包含于流体概念中。