This sea anemone is in danger. A dermasterias sea star is coming to devour it in the sped up footage above. But hop, wobble, squirm, shimmy! The sea anemone is off and away, launching a wiggly escape from the predator. We happened upon this Shape of Life video after researching a tweet that features this surprising video, filmed in Washington State.
But this is not just any sea anemone. This is the Stomphia coccinea, a sea anemone that can detach from its location and hop/swim/undulate away from danger. Some background from Wikipedia:
Although some species of sea anemone burrow in soft sediment, the majority are mainly sessile, attaching to a hard surface with their pedal disc, and tend to stay in the same spot for weeks or months at a time. They can move however, being able to creep around on their bases; this gliding can be seen with time-lapse photography but the motion is so slow as to be almost imperceptible to the naked eye…
Gonactinia prolifera is unusual in that it can both walk and swim; walking is by making a series of short, looping steps, rather like a caterpillar, attaching its tentacles to the substrate and drawing its base closer; swimming is done by rapid movements of the tentacles beating synchronously like oar strokes. Stomphia coccinea can swim by flexing its column, and the sea onion anemone inflates and casts itself loose, adopting a spherical shape and allowing itself to be rolled about by the waves and currents.
Filmed by C Tamis Photography, here’s another video example of the Stomphia escaping a Dermasterius imbricata:
Next: A Swimming Feather Starfish, the differences between a living and a dead sand dollar, sea cucumbers are underwater vacuum cleaners, a nine-armed sea star flipping itself over, and the melibe nudibranch grabs at food with a net-like mouth.h/t @JanFreedman.
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