Navigation Links
Giant squids' giant eyes: The better to see hungry whales with

It's no surprise that giant and colossal squid are big, but it's their eyes that are the real standouts when it comes to size, with diameters measuring two or three times that of any other animal. Now, researchers reporting online on March 15 in Current Biology, a Cell Press publication, have used complex computations to explain those massive peepers. Giant squids' 10-inch eyes allow them to see very large and hungry sperm whales from a distance in the pitch darkness of their deep-sea home.

According to the researchers' calculations, animals living underwater would have no use for such large eyes if the goal were to see an average object, such as prey smaller than themselves. That's why even the eyes of large whales aren't much more than 3.5 inches across.

"For seeing in dim light, a large eye is better than a small eye, simply because it picks up more light," said Dan-Eric Nilsson of Lund University. "But for animals that live in the sea or in lakes, the optical properties of water will severely restrict how far away things can be seen.

"Through complex computations we have found that for animals living in water, it does not pay to make eyes much bigger than an orange. Making eyes larger than that will only marginally improve vision, but eyes are expensive to build and maintain."

For Nilsson's team, that begged the question of why giant squid bother with their giant eyes. Using a mathematical model of underwater vision, they tested the benefits of very large eyes for a broad range of tasks under various light conditions. Those efforts showed that very large eyes aren't much better than smaller ones unless one wants to see something that is itself very big, like a whale.

Giant squid may also be unique in that they are powerful enough to escape a sperm whale once they've spotted one, Nilsson says. But how can giant squid see a sperm whale at depths beyond daylight's reach?

"The answer is bioluminescencelight produced by small gelatinous animals when they are disturbed by the whale moving through the water," Nilsson says. "It is well known that bioluminescence can reveal submarines at night, and diving sperm whales will become visible for the same reason."

The findings may also explain the large eyes of prehistoric ichthyosaurs, giant marine reptiles that looked something like dolphins, the researchers say. Although ichthyosaurs lived long before whales came along, they would have had to contend with giant predatory pliosaurs.

The new model can also be used to predict how far other animals can see underwater. "It is a powerful tool for understanding vision," Nilsson says.

Contact: Elisabeth (Lisa) Lyons
Cell Press

Related biology news :

1. 1,000 tags reveal mysteries of giant bluefin tuna
2. Conservation International gets support from Dreamworks Animation to protect giant pandas
3. Discovery of giant roaming deep sea protist provides new perspective on animal evolution
4. Doubling a gene in corn results in giant biomass
5. Tall tale of giant stingray circles the globe
6. Doubling a gene in corn results in giant biomass
7. Scientists rebuild giant moa using ancient DNA
8. Report documents the risks of giant invasive snakes in the US
9. Canopy giants and miniature fungi among 250 new species discovered in Kews 250th anniversary year
10. Microorganism may provide key to combating giant salvinia throughout Louisiana
11. Giant panda genome reveals new insights into the bears bamboo diet
Post Your Comments:
Related Image:
Giant squids' giant eyes: The better to see hungry whales with
(Date:6/2/2016)... 2016 The Department of Transport Management ... 44 million US Dollar project, for the , ... Personalization, Enrolment, and IT Infrastructure , to ... and implementation of Identity Management Solutions. Numerous renowned international vendors ... Decatur was selected for the most compliant and ...
(Date:5/24/2016)... patient care by providing unparalleled technology to leaders of the medical imaging industry.  As ... added to the range of products distributed by Ampronix. Photo - ... ... ... ...
(Date:5/9/2016)... Elevay is currently known as ... for high net worth professionals seeking travel for work ... world, there is still no substitute for a face-to-face ... your deal with a firm handshake. This is why ... of citizenship via investment programs like those offered by ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... 23, 2016   Boston Biomedical , an ... designed to target cancer stemness pathways, announced that ... Orphan Drug Designation from the U.S. Food and ... cancer, including gastroesophageal junction (GEJ) cancer. Napabucasin is ... inhibit cancer stemness pathways by targeting STAT3, and ...
(Date:6/23/2016)... Calif. , June 23, 2016  The Prostate Cancer Foundation ... increasingly precise treatments and faster cures for prostate cancer. Members of the Class ... across 15 countries. Read More About the Class of ... ... ...
(Date:6/23/2016)... ... June 23, 2016 , ... In a new case report published ... how a patient who developed lymphedema after being treated for breast cancer benefitted from ... the paradigm for dealing with this debilitating, frequent side effect of cancer treatment. ...
(Date:6/23/2016)... ... June 23, 2016 , ... ClinCapture, the only ... Center and will showcase its product’s latest features from June 26 to June ... scientific poster on Disrupting Clinical Trials in The Cloud during the conference. ...
Breaking Biology Technology: