A hallmark of animals is the coordination of whole-body movement. Neurons and muscles are central to this, yet coordinated movements also exist in sponges that lack these cell types. Sponges are sessile animals with a complex canal system for filter-feeding. They undergo whole-body movements resembling “contractions” that lead to canal closure and water expulsion. Here, we combine live 3D optical coherence microscopy, pharmacology, and functional proteomics to elucidate the sequence and …