Navigation Links
Dolphins maintain round-the-clock visual vigilance
Date:4/30/2009

Dolphins have a clever trick for overcoming sleep deprivation. Sam Ridgway from the US Navy Marine Mammal Program explains that they are able to send half of their brains to sleep while the other half remains conscious. What is more, the mammals seem to be able to remain continually vigilant for sounds for days on end. All of this made Ridgway and his colleagues from San Diego and Tel Aviv wonder whether the dolphins' unrelenting auditory vigilance tired them and took a toll on the animals' other senses? Ridgway and his team set about testing two dolphins' acoustic and visual vigilance over a 5 day period to find out how well they functioned after days without a break. The team publish their results on May 1 2009 in the Journal of Experimental Biology at http://jeb.biologists.org.

First Ridgway and his colleagues, Mandy Keogh, Mark Todd and Tricia Kamolnick, trained two dolphins to respond to a 1.5 s beep sounded randomly against a background of 0.5 s beeps every 30 s. Ridgway explains that the sounds were low enough for the dolphins to barely notice them as they swam through their enclosure, but the animals sprung into action every time they heard the 1.5 s tone, even after listening to the sounds for 5 days without a break. Their auditory vigilance remained as sharp as it had been 5 days earlier.

Next Allen Goldblatt and Don Carder designed a visual stimulus to test the dolphins' vigilance while they continued listening to the repetitive beeps. Knowing that the dolphins' binocular vision is limited because their eyes are situated on opposite sides of their heads, Kamolnick trained one of the dolphins, SAY, to recognise two shapes (either three horizontal red bars or one vertical green bar) with her right eye before training her to recognise the same shapes with the left eye, reasoning that if half of her brain was asleep during testing, the dolphin would only see the shapes through the eye connected to the conscious half of the brain. But the team were in for a surprise when they began training SAY's left eye. She already recognised the shapes, even though her left eye had not seen them previously. Ridgway explains that the information must be transferred between the two brain hemispheres and suspects that the dolphin's inter-hemispheric commissures, which connects the two halves, may transfer the visual information.

Having trained both dolphins to recognise the shapes, the hard part began: monitoring and rewarding the dolphins continually over a 5 day period while the team tested the animals' responses to both the sound and visual stimuli. Amazingly, even after 5 days of listening out for 1.5 s beeps amongst the 0.5 s beep background, the dolphins were still responding as accurately as they had done at the beginning of the experiment. The team also enticed the dolphins into a bay at night where they could be shown the horizontal and vertical bar shapes, and found that the dolphins were as sharp at the end of the 120 hour experiment as they had been at the beginning. And when the team checked the dolphins' blood for physical signs of sleep deprivation, they couldn't find any. After 5 days of unbroken vigilance the dolphins were in much better shape than the scientists.


'/>"/>

Contact: Kathryn Knight
kathryn@biologists.com
44-122-342-5525
The Company of Biologists
Source:Eurekalert

Related biology news :

1. Grays Paradox solved: Researchers discover secret of speedy dolphins
2. Whales and dolphins influence new wind turbine design
3. Killer whales, blind bats, discriminating dolphins, mating birds
4. Mercury contamination found in stranded Victorian dolphins
5. Migrating squid drove evolution of sonar in whales and dolphins, researchers argue
6. New book, Untangling the Double Helix, explores enzymes responsible for maintaining genome integrity
7. Astronauts may need more intense workouts to maintain muscle fitness in space
8. Maintaining the brains wiring in aging and disease
9. Niacins role in maintaining good cholesterol
10. UCR plant cell biologist to study how plant stem cells maintain and change their identity
11. 2 genes influence social behavior, visual-spatial performance in people with Williams syndrome
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:1/24/2017)... -- It sounds simple and harmless—an electronic sensor attached ... and alerts parents on their smart phones if, ... But pediatric experts argue that such devices may ... of medical benefits, especially to healthy babies. ... of healthy babies, promising peace of mind about ...
(Date:1/21/2017)... Research and Markets has announced the addition of the "Global ... ... recognition biometrics market to grow at a CAGR of 19.36% during ... scenario and the growth prospects of the global voice recognition biometrics ... the revenue generated from the sales of voice recognition biometrics including ...
(Date:1/19/2017)... , Jan. 19, 2017 ... user experience and security for consumer electronics, and ... payment processing systems and cybersecurity solutions, today announced ... enterprises and financial institutions worldwide to bolster security ... the end-to-end secure user authentication platforms they offer, ...
Breaking Biology News(10 mins):
(Date:2/23/2017)... 23, 2017  MIODx announced today that it ... immunotherapy technologies from the University of California, San ... to monitor a patient for response to immune ... The second license extends the technology with a ... to have an immune-related adverse event (IRAE) from ...
(Date:2/23/2017)... ... February 23, 2017 , ... Baltimore ... multiple immunoassay-based threat detection technologies by researchers from the Pacific National Northwest ... detection technology was found to have the best level of detection (LOD) ...
(Date:2/23/2017)... Feb. 23, 2017 Aviva Systems Biology ... the acquisition of GenWay Biotech Incorporated, a protein ... and product offering for both the research and ... growth and enhance capabilities for both entities. GenWay,s 18 ... assays will nicely complement ASB,s objective to become ...
(Date:2/22/2017)... ... 22, 2017 , ... Park Systems , a leader in Atomic Force ... SPIE attendees and Park customers on Feb. 27, 2017 from 12-2pm at ... Convention Center. The luncheon will feature a talk on Automated AFM for Small-Scale ...
Breaking Biology Technology: