Featured Research

from universities, journals, and other organizations

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

Date:
March 15, 2012
Source:
Cell Press
Summary:
Researchers 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.

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.
Credit: Nilsson et al.: “A unique advantage for giant eyes in giant squid.” Current Biology

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 bioluminescence -- light 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.


Story Source:

The above story is based on materials provided by Cell Press. Note: Materials may be edited for content and length.


Journal Reference:

  1. Nilsson et al. A Unique Advantage for Giant Eyes in Giant Squid. Current Biology, March 15, 2012 DOI: 10.1016/j.cub.2012.02.031

Cite This Page:

Cell Press. "Giant squids' giant eyes: The better to see hungry whales with." ScienceDaily. ScienceDaily, 15 March 2012. <www.sciencedaily.com/releases/2012/03/120315123011.htm>.
Cell Press. (2012, March 15). Giant squids' giant eyes: The better to see hungry whales with. ScienceDaily. Retrieved April 21, 2014 from www.sciencedaily.com/releases/2012/03/120315123011.htm
Cell Press. "Giant squids' giant eyes: The better to see hungry whales with." ScienceDaily. www.sciencedaily.com/releases/2012/03/120315123011.htm (accessed April 21, 2014).

Share This



More Plants & Animals News

Monday, April 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Mich. Boy Unearths 10,000-Year-Old Mastodon Tooth

Mich. Boy Unearths 10,000-Year-Old Mastodon Tooth

Newsy (Apr. 20, 2014) A 9-year-old Michigan boy was exploring a creek when he came across a 10,000-year-old tooth from a prehistoric mastodon. Video provided by Newsy
Powered by NewsLook.com
Vermont Goat Meat Gives Refugees Taste of Home

Vermont Goat Meat Gives Refugees Taste of Home

AP (Apr. 18, 2014) Dairy farmers and ethnic groups in Vermont are both benefiting from a unique collaborative effort that's feeding a growing need for fresh and affordable goat meat. (April 18) Video provided by AP
Powered by NewsLook.com
Man Claims He Found Loch Ness Monster With... Apple Maps?

Man Claims He Found Loch Ness Monster With... Apple Maps?

Newsy (Apr. 18, 2014) Andy Dixon showed the Daily Mail a screenshot of what he believes to be the mythical beast swimming just below the lake's surface. Video provided by Newsy
Powered by NewsLook.com
First Ever 'Female Penis' Discovered In Animal Kingdom

First Ever 'Female Penis' Discovered In Animal Kingdom

Newsy (Apr. 18, 2014) Not only are these newly discovered bugs' sex organs reversed, but they also mate for up to 70 hours. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

More Coverage


Basketball-Sized Eyes Help Squids Play Defense

Mar. 15, 2012 Researchers have used complex computations to explain squids' massive peepers. Giant squids' 10-inch eyes allow them to see very large and hungry sperm whales from a distance in the pitch ... read more
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins