For tiny creatures, swimming through water requires techniques very different than ours. Many, like this sea urchin larva, use hair-like cilia that they beat to push fluid near their bodies. The flows generated this way are beautiful and complex, as shown above. Importantly for the larva, the flows are asymmetric; that’s critical at these scales since any symmetric back-and-forth motion will keep the larva stuck in place. (Image credit: B. Shrestha et al.)
Ciliary Pathlines
