[MARMAM] Deep-diving pilot whales make cheap, but powerful, echolocation clicks with 50 µL of air

Ilias Foskolos lifosk at hotmail.com
Wed Nov 6 03:00:54 PST 2019

Dear Marmam and ECS members (sorry for crossposting),

on behalf of my coauthors, I am pleased to inform you on our recent publication in Nature Scientific Reports. We show that deep-diving pilot whales can echolocate almost continuously whilst foraging at depth by using tiny amounts of air to make each click and by capturing and recycling the used air. The small air volumes mean that echolocation doesn’t take much energy.

The full reference and abstract are found below:

Foskolos, I., Aguilar de Soto, N., Madsen, P.T. & Johnson, M. Deep-diving pilot whales make cheap, but powerful, echolocation clicks with 50 µL of air. Sci. Rep. 9, 15720 (2019).

Echolocating toothed whales produce powerful clicks pneumatically to detect prey in the deep sea where this long-range sensory channel makes them formidable top predators. However, air supplies for sound production compress with depth following Boyle’s law suggesting that deep-diving whales must use very small air volumes per echolocation click to facilitate continuous sensory flow in foraging dives. Here we test this hypothesis by analysing click-induced acoustic resonances in the nasal air sacs, recorded by biologging tags. Using 27000 clicks from 102 dives of 23 tagged pilot whales (Globicephala macrorhynchus), we show that click production requires only 50 µL of air/click at 500 m depth increasing gradually to 100 µL at 1000 m. With such small air volumes, the metabolic cost of sound production is on the order of 40 J per dive which is a negligible fraction of the field metabolic rate. Nonetheless, whales must make frequent pauses in echolocation to recycle air between nasal sacs. Thus, frugal use of air and periodic recycling of very limited air volumes enable pilot whales, and likely other toothed whales, to echolocate cheaply and almost continuously throughout foraging dives, providing them with a strong sensory advantage in diverse aquatic habitats.

This is an Open Access paper and it is freely accessible online at: https://www.nature.com/articles/s41598-019-51619-6.

If you have any problems with the above link or any questions, please feel free to contact me at lifosk at hotmail.com<mailto:lifosk at hotmail.com>.

Best wishes,

Ilias Foskolos, PhD Fellow
Marine Bioacoustics Lab<https://marinebioacoustics.wordpress.com/>

Zoophysiology, Dept. Bioscience
Aarhus University
C.F. Møllers Allé 3, Building 1131
DK-8000 Aarhus C, Denmark
E-mail: lifosk at hotmail.com<mailto:lifosk at hotmail.com>

Twitter: theclickitclick<https://twitter.com/theclickitclick>
Phone: (+45) 50656572

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