Can invertebrates sneeze?
Sponges probably can. These simple, ancient creatures were possibly the first multicellular animals to evolve, at least 600 million years ago. It’s generally been assumed that once the swimming larvae settle on the seabed, sponges spend the rest of their uneventful adult lives sitting still, endlessly filtering seawater through the pores in their bodies. But recently, scientists studied 30 years’ worth of time-lapse photography, shot 4,000m deep off the coast of California, and spotted sponges rhythmically expanding and contracting. One possible explanation is that they are expelling irritating particles from their bodies, like a cough or a sneeze. It’s perhaps unsurprising that nobody noticed the sponges’ slow-motion expulsions, which take weeks or months between the expanding ‘ahh’ to the release of the ‘choo’.