Dendraster excentricus

D. excentricus (Pacific sand dollar) larva show very frequent behavioral transitions from periods of upward swimming to briefly sink down the water-column. Multi-scale tracking using Gravity Machine has revealed a novel aspect of this behavior wherein each transition causes the larva to choose a new direction of upward swimming. The result of many such transitions is that the larva scans a significantly wider area of the water column. This is visible in the resulting 3D trajectory, shown to the right of the video having substantial horizontal drift. Such observations highlight the utility of multi-scale tracking tools where the micro-macro coupling is possible within the same dataset.