Manta rays were built for speed — and to filter feed.
The aerodynamic ocean dwellers efficiently separate plankton from seawater using a previously unknown kind of filtration system that resists clogs and captures tiny bits of plankton, researchers report September 26 in Science Advances.
Mantas are filter feeders, like many other ocean creatures. They pull plankton-laden seawater into their mouths, where arrays of cartilaginous fibers helps them swallow the plankton but release the seawater. For some filter feeders, the process can be compared to straining a pot of pasta and letting the water run through, says coauthor Misty Paig-Tran, a marine biologist at California State University, Fullerton. But for mantas, that analogy doesn’t quite work. Some of the plankton that mantas eat is small enough to slip through the gaps — more like grains of rice than chunky pasta shells. And mantas don’t have sticky filter mucus to snag these small particles, as sponges and bryozoans do.