Navigation Links
Seals sense shapes using their whiskers to feel wakes
Date:5/11/2011

Hunting in the North Sea, harbour seals often encounter murky water that impedes their vision; but it doesn't affect their ability to chase prey. Extending their vibration-sensitive whiskers, the mammals are almost as efficient at pursuing their quarry as they would be if guided by sight. Wolf Hanke and his colleagues from the University of Rostock, Germany, are fascinated by how harbour seals perceive the world through their flow-sensitive vibrissae. Having already found that seals can pick up and follow fish wakes up to 35 seconds after the prey has passed and knowing that a fish's size and shape can dramatically affect its wake structure, graduate student Sven Wieskotten decided to find out how well seals can distinguish between the wakes of objects with different shapes and sizes. The team publishes their discovery that harbour seals can detect differences in the wakes generated by differently shaped objects using only their whiskers in The Journal of Experimental Biology at http://jeb.biologists.org/content/214/11/1922.abstract

Teaming up with Henry the harbour seal at the Marine Science Centre, Germany, Hanke, Wieskotten and their colleagues, Lars Miersch and Guido Dehnhardt, began testing Henry's ability to distinguish between the wakes of differently sized paddles. The researchers blindfolded Henry and covered his ears, then they swept a paddle through a large box in Henry's enclosure and allowed him to enter it 3 seconds later. Having trained Henry to press a target outside the enclosure when he recognised the wake of a standard paddle and to press a different target when he recognised the wake from a larger or smaller paddle, the team found that Henry could distinguish between paddles that differed by as little as 2.8cm in width.

Then, the team tested which aspects of the wake the seal picked up on. 'We randomised the speeds of the paddles so that the maximum flow velocity wasn't a distinguishing cue for the widest paddles, but the structure of the wake had to be recognised by the seal and he could do that too, but with slightly less accuracy,' remembers Hanke.

Next, the team varied the paddle shapes and asked Henry to distinguish between the wakes of triangular, cylindrical, flat and undulating paddles. The seal successfully distinguished between the flat and cylindrical paddles, the flat and undulating paddles and the undulating and cylindrical paddles after they were swept through the enclosure. However, he had problems distinguishing the triangular paddle from the undulating or cylindrical shapes.

Having found that Henry can distinguish between the wakes of different passing objects and investigated the structure of each paddle's wake with digital particle image velocimetry, Hanke says, 'It is difficult to tell which part of the wake serves the animal most and which aided only a little.' So, Hanke is keen to test Henry's responses to single vortices to find out which wake components might give a fish's size and shape away. He explains that hunting seals have to optimise the amount of energy that they ingest while hunting so, if a seal can distinguish between small skinny fish which cost too much to pursue and the perfect lunch based on their wakes alone, that could improve its hunting efficiency enormously.


'/>"/>

Contact: Kathryn Knight
kathryn@biologists.com
44-787-634-4333
The Company of Biologists
Source:Eurekalert

Related biology news :

1. Mercury pollution causes immune damage to harbor seals
2. NTU seals global partnerships on environmental sciences R&D
3. Fossil evidence of missing link in the origin of seals, sea lions, walruses found in Canadian Arctic
4. Seals quickly respond to gain and loss of habitat under climate change
5. Harbor seals whiskers as good at detecting fish as echolocating dolphins
6. High-tech software, umanned planes allow scientists to keep tabs on Arctic seals
7. NOAA scientists find killer whales in Antarctic waters prefer weddell seals over other prey
8. Painful heat sensed by painless in flies
9. Deprived of a sense of smell, worms live longer
10. Girls have superior sense of taste to boys
11. Liking sweets makes sense for kids
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/12/2016)... May 12, 2016 WearablesResearch.com , a ... the overview results from the Q1 wave of its ... wave was consumers, receptivity to a program where they ... a health insurance company. "We were surprised ... says Michael LaColla , CEO of Troubadour Research, ...
(Date:4/28/2016)... and BANGALORE, India , April ... EdgeVerve Systems, a product subsidiary of Infosys (NYSE: ... today announced a global partnership that will provide ... to use mobile banking and payment services.      ... a key innovation area for financial services, but it also ...
(Date:4/26/2016)... DUBLIN , April 27, 2016 ... of the  "Global Multi-modal Biometrics Market 2016-2020"  report ... ) , The analysts forecast ... a CAGR of 15.49% during the period 2016-2020.  ... a number of sectors such as the healthcare, ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... , June 23, 2016 /PRNewswire/ - FACIT has ... Ontario biotechnology company, Propellon Therapeutics Inc. ... and commercialization of a portfolio of first-in-class WDR5 ... targets such as WDR5 represent an exciting class ... in precision medicine for cancer patients. Substantial advances ...
(Date:6/23/2016)... June 23, 2016  The Prostate Cancer Foundation (PCF) is pleased ... and faster cures for prostate cancer. Members of the Class of 2016 were ... Read More About the Class of 2016 PCF Young ... ... ...
(Date:6/23/2016)... ... June 23, 2016 , ... STACS DNA Inc., the sample tracking software ... State Crime Laboratory, has joined STACS DNA as a Field Application Specialist. , ... Tremblay, President and COO of STACS DNA. “In further expanding our capacity as a ...
(Date:6/23/2016)... , June 23, 2016 ... Hematology Review, 2016;12(1):22-8 http://doi.org/10.17925/OHR.2016.12.01.22 ... , the peer-reviewed journal from touchONCOLOGY, Andrew ... escalating cost of cancer care is placing an ... result of expensive biologic therapies. With the patents ...
Breaking Biology Technology: