This mode of organismal locomotion suggests new explanations for the plasticity of sponge morphology, seems not to have been reported from other metazoans, and has significant ecological implications.The flagella aid in the free swimming phase of sponge development and play an important role in finding a suitable substrate to settle upon. Our observations suggest that the displacement of sponges is achieved by the cumulative crawling locomotion of the cells that compose the sponge's lower surface. Neither the patterns of wrinkling produced in rubber substrata nor the distributions of adhesive contacts seen by interference reflection microscopy show evidence of periodic, propagating waves of surface contractions, such as would be expected if the sponges' mechanism of locomotion were by peristalsis or locomotory waves. Other similarities include the orientation of sponge locomotion along grooves and the preferential extension onto more adhesive substrata. Sponge locomotion was found to be mechanically similar to the spreading of cell sheets in tissue culture both with respect to exertion of traction (which causes the wrinkling of rubber substrata) and with respect to the patterns of adhesive contacts formed with the substratum (as observed by interference reflection microscopy). Time-lapse cinemicrography and scanning electron microscopy reveal that moving sponges possess distinctive leading edges composed of motile cells.

Sequential tracing of sponge outlines on aquarium walls shows that sponges can crawl up to 160 microns/hr (4 mm/day). Active locomotion by individual marine and freshwater sponges across glass, plastic and rubber substrata has been studied in relation to the behavior of the sponges' component cells.

Do sponges have legs to move