Archer fish hunt insects with water jet 6 times stronger than their muscular power

Fish modulate water jet dynamics to increase impact to prey

2012-10-25

(Press-News.org) Archer fish knock their insect prey out of overhanging vegetation with a jet of water several times more powerful than the fish's muscles. New research now shows that the fish generate this power externally using water dynamics rather than with any specialized internal organs. The research, published Oct. 24 in the open access journal PLOS ONE by Alberto Vailati and colleagues from the University of Milan, provides the first explanation for how archer fish can generate such powerful jets to capture their prey.

Other animals like chameleons and salamanders store energy in collagen fibers in their bodies and abruptly release this stored energy to project their tongues at high speeds, but previous studies on archer fish have ruled out such specialized organs as the source of the powerful water jets.

VIDEO: This is a slow-motion movie of archer fish shooting at prey and eating it when it falls into water.
Click here for more information.

The authors of the current study used high-speed video recordings of archer fish knocking insects out of overhanging plants to study the mechanics of the water jet and found that the fish could modulate the velocity of the jet to create a single large water drop that hit the prey with a large force. According to the authors, this approach avoids the evolutionary costs needed to develop special internal structures to store these large amounts of energy.

"The origin of the effectiveness of the jet squirted by archer fish has been searched for inside of the fish for nearly 250 years. The striking finding of our work is that a large amplification of muscular power occurs outside of the fish and leads to a very powerful impact of the jet with the prey" says Vailati.

VIDEO: This is a movie of archer fish firing a flurry of blows at prey.
Click here for more information.

INFORMATION:

Citation: Vailati A, Zinnato L, Cerbino R (2012) How Archer Fish Achieve a Powerful Impact: Hydrodynamic Instability of a Pulsed Jet in Toxotes jaculatrix. PLoS ONE 7(10): e47867. doi:10.1371/journal.pone.0047867

Financial Disclosure: The authors have no support or funding to report.

Competing Interest Statement: The authors have declared that no competing interests exist.

PLEASE LINK TO THE SCIENTIFIC ARTICLE IN ONLINE VERSIONS OF YOUR REPORT (URL goes live after the embargo ends):

http://dx.plos.org/10.1371/journal.pone.0047867

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Archer fish hunt insects with water jet 6 times stronger than their muscular power

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