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WHEN THEY CAN'T HEAR THEY CAN'T LIVE
Sound and Sea Creatures
Audio Spectrum

Blog Entry

Crustaceans need ears too!

A preponderance of marine bioacoustic work has been focused on marine mammals – whales, dolphins, and pinnipeds. This is in large part due to the “charismatic megafauna” paradigm where big, complicated animals with recognizable expressions attract most human interest.

While fish – particularly large or colorful species can capture our attention under this same rubric, most scientific research on fish is advanced due to their commercial importance. Critters further down on the ‘charisma scale’ even while equally complicated in their adaptations are typically not studied, so it was great to hear OCR pal and Biologist Erica Staaterman’s presentation on mantis shrimp at the recent “Acoustic Communication by Animals” Symposium.

Even better was that her work was picked up by “Science Daily” and distributed to a wider public.

The mantis shrimp are visually intriguing; being some 8” to 10” (and up to 15”) long with a pair of incredibly complicated eyes that can sort out twelve colors and reconcile polarized light. Some species visually communicate by modulating fluorescence on their bodies, and some species live in monogamous pairs for up to 20 years!

With all of these attributes it is likely that vision is their dominant perceptual adaptation, but Erica found that they also communicate with sound through a low frequency rumble or purr. In the realm of human perceptions this isn’t Grammy material, but when pitch-shifted up an octave the call and response patterns become more apparent.

She also found that listening to the shrimp was very different in the wild from listening to them in a tank. The shrimps’ communications were, “so synchronized they sounded like a chorus.”

We can only speculate what they are expressing with these sounds, but Erica’s work has rolled back just a little more of the mystery of the deep. [Read Ocean-Noise post on 'chorusing']

Her paper was published in Aquatic Biology.

Posted on September 22, 2011 at 2:23 pm