@article {57296,
	title = {Remarkably loud snaps during mouth-fighting by a sponge-dwelling worm},
	journal = {Current Biology},
	volume = {29},
	year = {2019},
	month = {Jan-07-2019},
	pages = {R617 - R618},
	abstract = {<p>Many aquatic animals, including mammals, fishes, crustaceans and insects, produce loud sounds underwater 1, 2, 3, 4, 5, 6. Soft-bodied worms would seem unlikely to produce a loud snap or pop because such brief, intense sounds normally require extreme movements and sophisticated energy storage and release mechanisms [5]. Surprisingly, we discovered a segmented marine worm that makes loud popping sounds during a highly stereotyped intraspecific agonistic behavior we call \&lsquo;mouth fighting\&rsquo;. These sounds \&mdash; sound pressures up to 157 dB re 1 \&mu;Pa at 1 m, with frequencies in the 1\&ndash;100 kHz range and a strong signal at \&sim;6.9 kHz \&mdash; are comparable to those made by snapping shrimps, which are among the most intense biological sounds that have been measured in the sea [6]. We suggest a novel mechanism for generating ultrafast movements and loud sounds in a soft-bodied animal: thick, muscular pharyngeal walls appear to allow energy storage and cocking; this permits extremely rapid expansion of the pharynx within the worm\&rsquo;s body during the strike, which yields an intense popping sound (likely via cavitation) and a rapid influx of water. Clearly, even soft-bodied marine invertebrates can produce remarkably loud sounds underwater. How they do so remains an intriguing biomechanical puzzle that hints at a new type of extreme biology.</p>
},
	issn = {09609822},
	doi = {10.1016/j.cub.2019.05.047},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0960982219306177},
	author = {Goto, Ryutaro and Hirabayashi, Isao and Palmer, A. Richard}
}
