Mobility and self-righting by a free-living mushroom coral through pulsed inflation

Locomotion and self-righting in an overturned juvenile mushroom coral, Herpolitha limax , was documented and analyzed by the use of time-lapse photography. The coral used a series of rhythmic polyp expansions and contractions to move itself. The complete process of the righting took place within six hours, consisting of a stationary phase, a shuffle phase, a sudden flip-over, and a recovery phase. The mouth of the coral may be used to eject water, which can perhaps be applied as a means of jet propulsion. This report demonstrates that time-lapse photography can be applied to analyze all kinds of behavior in marine invertebrates that move too slow for regular observations.