This worm swims while rowing with his whole body

The Tomopteris live in the open water, far from the sand and rocks on which sea worms are readily imagined. Many have a transparent body that makes them discreet in the dark. But their singularity appears especially when they start swimming.

They ripple laterally while rowing with their fleshy appendages, the parapods. Movements are coordinated. Researchers from MBARI and the Smithsonian used fast videos and lasers revealing the flow of water to study this locomotion.

Not all species have the same defenses: some can release a luminous liquid, others roll into a shape reminiscent of a gelatinous animal. Swimming remains their way of exploiting an environment without a support point. This worm does not try to reach the bottom to move forward: it finds its holds in the water itself.