This laser-light illumination of particles in water appears to show us how a creature moves around by using carefully-directed jets of water, up and down its entire body. But that’s not what we’re actually seeing.
What we’re seeing is a whole colony of animals moving through carefully-directed jets of water up and down the length of their whole colony. This is Nanomia bijuga. It’s a siphonophore, a class of animals that live indivisibly as one colony, despite technically being made up of many different creatures. Think of an ant colony, except its members are even less able to survive on their own.
What’s amazing about this particular animal is it doesn’t just use different animals to accomplish one task, it divides the task up, according to age. Younger members are too small to provide powerful jets of water. So they bud near the front of the colony and make the small, gentle jets that allow the siphonophore to steer itself. As they get older, new buds form ahead of them. The older ones change their orientation slightly, but more importantly they change their behavior, giving undirected but powerful thrusts, which move Nanomia bijuga through the water more quickly.