![]() ![]() But new accidental findings may show we’ve underestimated them. They’re also the least evolutionarily advanced creatures on the planet. Sponges may look like plants, but they’re animals-some of the longest-lived on Earth, with a few living more than 10,000 years. Or are sponges able to move faster sporadically? Credit: AWI OFOBS team, PS101 With paces of just millimeters per year, some tracks may have taken hundreds of years or more to create. 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.Sponge-spicule trails are typically tan and may move uphill and change directions like this one. 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. ![]()
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