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:2/7/2017)... MINNETONKA, Minn. , Feb. 7, 2017   ... that supports the entire spectrum of clinical research, is ... iMedNet , its innovative, highly flexible and ... iMedNet customers. iMedNet is a ... only provides Electronic Data Capture (EDC), but also delivers ...
(Date:2/3/2017)... Feb. 3, 2017 A new independent identity ... Partners, LLP (IdSP) . Designed to fill a critical ... identity market, founding partners Mark Crego and ... years just in identity expertise that span federal governments, ... leadership. The Crego-Kephart combined expertise has a common theme ...
(Date:1/31/2017)... CAMBRIDGE, Mass. , Jan. 31, 2017 /PRNewswire-USNewswire/ ... develop novel therapies for the treatment of bacterial ... generation set of antibacterial candidates from Pro Bono ... the increased prevalence of multi-drug resistant forms of ... by Cantab Anti Infectives Ltd, a PBB group ...
Breaking Biology News(10 mins):
(Date:2/23/2017)... The Fight Against Cancer Innovation Trust (FACIT) and the ... report that Fusion Pharmaceuticals Inc. (Fusion) has closed a ... – JJDC, Inc. (JJDC) as the lead investor. Additional, ... and Genesys Capital, as well as founding investor FACIT.  ... ...
(Date:2/23/2017)... , Feb. 23, 2017  In Atlanta, it seems ... fashion, and culture intertwine to create an expressive and dynamic ... reflect this energy and contribute to it. ... Hair Fairies seeks to carry on that tradition ... Atlanta salon is the newest of ...
(Date:2/23/2017)... , Feb. 23, 2017  Imanis Life ... product line of oncolytic vaccinia viruses for virotherapy ... as part of Genelux,s proprietary, vaccinia virus-based technology ... excited to enter into a partnership with Genelux ... oncolytic vaccinia viruses for use in research," said ...
(Date:2/23/2017)... ... February 23, 2017 , ... ... that in a published evaluation of multiple immunoassay-based threat detection technologies by ... Energy Laboratory, PathSensors’ CANARY® biosensor threat detection technology was found to have ...
Breaking Biology Technology: