Maneuvering Performance in the Colonial Siphonophore, .

The colonial cnidarian, , is highly proficient at moving in three-dimensional space through forward swimming, reverse swimming and turning. We used high speed videography, particle tracking, and particle image velocimetry (PIV) with frame rates up to 6400 s to study the kinematics and fluid mechanics of during turning and reversing. achieved turns with high maneuverability (mean length-specific turning radius, R/L = 0.15 ± 0.10) and agility (mean angular velocity, ω = 104 ± 41 deg. s). The maximum angular velocity of , 215 deg. s, exceeded that of many vertebrates with more complex body forms and neurocircuitry. Through the combination of rapid nectophore contraction and velum modulation, generated high speed, narrow jets (maximum = 1063 ± 176 mm s; 295 nectophore lengths s) and thrust vectoring, which enabled high speed reverse swimming (maximum = 134 ± 28 mm s; 37 nectophore lengths s) that matched previously reported forward swimming speeds. A 1:1 ratio of forward to reverse swimming speed has not been recorded in other swimming organisms. Taken together, the colonial architecture, simple neurocircuitry, and tightly controlled pulsed jets by allow for a diverse repertoire of movements. Considering the further advantages of scalability and redundancy in colonies, is a model system for informing underwater propulsion and navigation of complex environments.