Feather stars (Florometra serratissima) are unique in being able to swim. They do so by graceful undulation of their 10 arms, 5 going upwards and the other 5 going downwards. The propulsive mode is sculling, the same mode as used by human swimmers and fishes. A cluster of gripping appendages or cirri provides attachment, but these are readily released prior to swimming. Little is known about natural predators of feather stars, but swimming would seem an excellent defense against such potential predators as fast-moving sunflower stars.