Nav: Home

Cuttlefish hear bow wave of looming danger

January 11, 2018

Imagine trying to get close to your dinner only for it to be swept aside by your approach; this is the scenario faced by aquatic creatures every day as they try to snap up a tasty morsel. 'It is impossible to eat something underwater without creating a hydrodynamic disturbance', says Maria Wilson from the University of Southern Denmark, describing how a predator's approach is heralded by a bow wave that arrives before the final slurp as a hungry hunter sucks up its prey. Explaining that the surge of water produces low-pitched (low-frequency) vibrations, Wilson and her colleagues, Jens Haga and Hans Erik Karlsen from the University of Oslo, Norway, wondered whether cuttlefish - the preferred delicacy of many large aquatic predators - might keep an ear out for the approaching attack, and, if so, in which direction they would swim to evade the predator. The team publishes their discovery that cuttlefish can hear approaching bow waves and swim in the same direction as the water to evade capture in Journal of Experimental Biology at http://jeb.biologists.org.

Wilson explains that cuttlefish ears - statocysts - which are buried in their heads, are fine tuned to low-pitched sounds and could allow the animals to sense the vibrations that herald an attack in dim and cloudy conditions. So, she and Karlsen decided to test the cuttlefish's reactions to low-frequency vibrations in a tank. However, with their sensitive vision and sensors that detect water flow over the skin, cuttlefish are easily startled, so the team used a specialised tank designed by Karlsen to make sure that the animals were not side-tracked by other distractions. In addition, Wilson made sure that the environment remained calm, in case the animals released ink into the water. 'When that happened, we had to remove the cuttlefish and clean everything', says Wilson, who even took a shot of ink in the face on one occasion: 'Almost as if it did it on purpose', she laughs.

Having settled individual cuttlefish in the tank, Wilson, Karlsen and Haga simulated a predator's approach, and the sucking attack, with vibrations generated by shakers on the side of the tank in light and dark conditions. Filming the cuttlefish's responses as the vibrations washed over the animals, the team could see that the cuttlefish were aware of the disturbance as they changed the patterns on their skin. And when the cuttlefish encountered the vibrations simulating a predator's approach, they turned to flee in the same direction that the bow wave was travelling, regardless of whether the lights were on or off.

However, when the cuttlefish were startled by a pressure wave simulating the final suck as the predator struck, the cuttlefish again moved in the same direction as the flowing water, '[which] would move the cuttlefish directly into the mouth of the predator!' says Wilson. Although she was initially surprised by the counterintuitive behaviour, Wilson suspects that in real life the animals may have already taken evasive action before they sensed the impending slurp.

The team also tried to distract the hungry cuttlefish with a movie of tasty shrimp. 'They only had to see the video once and when the screen went black, they would ... just wait for the show to start again', recalls Wilson. In fact, the cuttlefish were so engaged by the prospect of food that the team had to turn up the shakers, producing the simulated attack to get the animal's attention.

So, cuttlefish depend on their ears to evade an approaching attack and Wilson is concerned that the fog of low-pitched noise produced by shipping may mask bow wave warning signals, leaving cuttlefish vulnerable to predators that they currently outwit.
-end-
IF REPORTING THIS STORY, PLEASE MENTION JOURNAL OF EXPERIMENTAL BIOLOGY AS THE SOURCE AND, IF REPORTING ONLINE, PLEASE CARRY A LINK TO: http://jeb.biologists.org/content/221/1/jeb166074

REFERENCE: Wilson, M., Haga, J. Å. R. and Karlsen, H. E. (2018). Behavioural responses to infrasonic particle acceleration in cuttlefish. J. Exp. Biol. 221, doi: 10.1242/jeb166074.

DOI: 10.1242/jeb.166074.

This article is posted on this site to give advance access to other authorised media who may wish to report on this story. Full attribution is required, and if reporting online a link to jeb.biologists.com is also required. The story posted here is COPYRIGHTED. Therefore advance permission is required before any and every reproduction of each article in full. PLEASE CONTACT permissions@biologists.com

THIS ARTICLE IS EMBARGOED UNTIL THURSDAY, 11 JANUARY 2018, 18:00 HRS EST (23:00 HRS GMT)

The Company of Biologists

Related Predators Articles:

Marine predators: Bigger in size with an appetite to match
The size of marine invertebrate predators has increased over the past 500 million years, while the size of their prey has not, a new study reveals.
Predators are real lowlifes
By deploying green clay caterpillar models across six continents, researchers unmasked an important global pattern.
Fish step up to lead when predators are near
Researchers from the University of Bristol have discovered that some fish within a shoal take on the responsibilities of leader when they are under threat from predators.
Restoring predators and prey together speeds recovery
Restoring predator and prey species together helps accelerate ecosystem recovery efforts compared to pursuing restoration of one species at a time, new research concludes.
Recovering predators and prey
Researchers show how simultaneously restoring predators and prey is much faster and more effective than doing so one at a time.
Reducing pressure on predators, prey simultaneously is best for species' recovery
Reducing human pressure on exploited predators and prey at the same time is the best way to help their populations recover, a new study indicates.
When it comes to predators, size matters
When it comes to predators, scientists find larger sheephead that consume bigger urchins help keep that population under control.
Birds of a feather flock together to confuse potential predators
Scientists from the universities of Bristol and Groningen, in The Netherlands, have created a computer game style experiment which sheds new light on the reasons why starlings flock in massive swirling groups over wintering grounds.
For viral predators of bacteria, sensitivity can be contagious
Scientists have shown for the first time how bacteria with resistance to a viral predator can become susceptible to it after spending time in the company of other susceptible or 'sensitive' bacteria.
How miniature predators get their favorite soil bacteria
Tiny predators in the soil can literally sniff out their prey: soil bacteria, which communicate with each other using scent.

Related Predators Reading:

Predator: The Original Comics Series - Concrete Jungle and Other Stories
by Mark Verheiden (Author), Chris Warner (Illustrator), Same de la Rosa (Illustrator), David Jackson (Illustrator), Chris Chalenor (Illustrator)

Ultimate Predatorpedia: The Most Complete Predator Reference Ever (National Geographic Kids)
by Christina Wilsdon (Author)

100 Things Predators Fans Should Know & Do Before They Die (100 Things...Fans Should Know)
by John Glennon (Author)

The Predator: The Art and Making of the Film
by James Nolan (Author)

Aliens Predator Prometheus AVP: The Complete Life and Death
by Dan Abnett (Author), Brian Albert Thies (Illustrator), Andrea Mutti (Illustrator), Moritat (Illustrator)

Nashville Predators:: The Making of Smashville (Sports)
by Justin B. Bradford (Author), Pete Weber (Foreword)

Smart Kids: Predators: The World's Deadliest Hunters
by Roger Priddy (Author)

Prehistoric Predators
by Brian Switek (Author), Julius Csotonyi (Illustrator)

DC Comics/Dark Horse: Batman vs. Predator (Batman DC Comics Dark Horse Comics)
by Dave Gibbons (Author), Andy Kubert (Illustrator)

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Circular
We're told if the economy is growing, and if we keep producing, that's a good thing. But at what cost? This hour, TED speakers explore circular systems that regenerate and re-use what we already have. Guests include economist Kate Raworth, environmental activist Tristram Stuart, landscape architect Kate Orff, entrepreneur David Katz, and graphic designer Jessi Arrington.
Now Playing: Science for the People

#503 Postpartum Blues (Rebroadcast)
When a woman gives birth, it seems like everyone wants to know how the baby is doing. What does it weigh? Is it breathing right? Did it cry? But it turns out that, in the United States, we're not doing to great at asking how the mom, who just pushed something the size of a pot roast out of something the size of a Cheerio, is doing. This week we talk to anthropologist Kate Clancy about her postpartum experience and how it is becoming distressingly common, and we speak with Julie Wiebe about prolapse, what it is and how it's...