Mantis shrimp (Stomatopoda) are ancient beasts, thought to have originated over 250 million years ago.In that time, they have evolved a remarkable suite of sensory adaptations, including arguably one of the most complex visual systems of any organism. Is it not surprising, then, that they also have evolved mechanisms of communication with sounds and vibrations? Perhaps it is surprising, though, that the first recordings of these animals were published in 2006 and were acquired simply by placing our hydrophones in tanks containing California mantis shrimp, Hemisquilla californiensis. We named the remarkable low-frequency infra-sounds emanating from these animals, the “rumble”, after similar sounds produced by elephants. While these first recordings offer insights into the frequency spectra and other characteristics of the vibrations, and also the thrill of hearing such an eerie noise, we are still left with many unanswered questions. These animals make sound when interacting with potential predators, but our recent fieldwork suggests that the use of these sounds may extend to more complex social interactions among their networks of subterranean, muddy burrows. Also, the source of the vibration is apparently from muscles vibrating the edge of the carapace which happens to exhibit a bright pink, polarized spot. Could this be a multi-modal signal, including both visual and vibratory cues?
We are left to wonder how many other creatures remain unheard in the ocean…waiting for us to simply take a few moments to listen, record and explore.