Featured Research

from universities, journals, and other organizations

Deep-sea squid can 'jettison arms' as defensive tactic

Date:
August 2, 2012
Source:
University of Rhode Island
Summary:
A researcher has observed a never-before-seen defensive strategy used by a small species of deep-sea squid in which the animal counter-attacks a predator and then leaves the tips of its arms attached to the predator as a distraction.

Still image from video of the discovery.
Credit: Monterey Bay Aquarium Research Institute

A postdoctoral researcher at the University of Rhode Island has observed a never-before-seen defensive strategy used by a small species of deep-sea squid in which the animal counter-attacks a predator and then leaves the tips of its arms attached to the predator as a distraction.

Stephanie Bush said that when the foot-long octopus squid (Octopoteuthis deletron) found deep in the northeast Pacific Ocean "jettisons its arms" in self-defense, the bioluminescent tips continue to twitch and glow, creating a diversion that enables the squid to escape from predators.

"If a predator is trying to attack them, they may dig the hooks on their arms into the predator's skin. Then the squid jets away and leaves its arm tips stuck to the predator," explained Bush. "The wriggling, bioluminescing arms might give the predator pause enough to allow the squid to get away."

The discovery was published in the July issue of the journal Marine Ecology Progress Series.

While Bush was a graduate researcher working with the Midwater Ecology Lab at the Monterey Bay Aquarium Research Institute, she observed that many octopus squid had arms of different lengths. Scientists had speculated that they may release their arms, just as lizards can release their tails when attacked, but no one had seen it happen. Using a remotely operated vehicle in the Monterey Bay Submarine Canyon off the coast of California, Bush poked at a squid with a bottlebrush.

"The very first time we tried it, the squid spread its arms wide and it was lighting up like fireworks," she said. "It then came forward and grabbed the bottlebrush and jetted backwards, leaving two arms on the bottlebrush. We think the hooks on its arms latched onto the bristles of the brush, and that was enough for the arms to just pop off."

The squid are able to re-grow their missing arms.

"There is definitely an energy cost associated with this behavior, but the cost is less than being dead," Bush said.

In further experiments, Bush found that some octopus squid appeared hesitant to sacrifice their limbs, but some did so after being prodded several times. When she provoked seven other squid species similarly, none dropped their arm tips.

Bush's research on squid began in 2003 when she decided to investigate the assumptions that some scientists had made about deep-sea animals.

"Scientists had assumed that squid living in the deep-sea would not release ink as a defensive measure, but all the species I've observed did release ink," she said. "They assumed that because they're in the dark all day every day that they're not doing the same things that shallow water squids are doing. They also assumed that deep-sea squid don't change color because of the dark, but they do."

The URI scientist's current research focuses on a tiny squid that lives in the Gulf of California that migrates every day from the dark depths where there is little oxygen to the surface waters to feed. She is examining their oxygen consumption rates and how increasing water temperatures will affect their survival.

"They're a really abundant species in the Gulf, so presumably if they are that abundant, they must be feeding on lots of different things and there must be lots of things feeding on them," Bush said. "They could be very important to the health of the ecosystem."


Story Source:

The above story is based on materials provided by University of Rhode Island. Note: Materials may be edited for content and length.


Journal Reference:

  1. SL Bush. Economy of arm autotomy in the mesopelagic squid Octopoteuthis deletron. Marine Ecology Progress Series, 2012; 458: 133 DOI: 10.3354/meps09714

Cite This Page:

University of Rhode Island. "Deep-sea squid can 'jettison arms' as defensive tactic." ScienceDaily. ScienceDaily, 2 August 2012. <www.sciencedaily.com/releases/2012/08/120802150437.htm>.
University of Rhode Island. (2012, August 2). Deep-sea squid can 'jettison arms' as defensive tactic. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2012/08/120802150437.htm
University of Rhode Island. "Deep-sea squid can 'jettison arms' as defensive tactic." ScienceDaily. www.sciencedaily.com/releases/2012/08/120802150437.htm (accessed October 20, 2014).

Share This



More Plants & Animals News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Rare Lion Cubs Make Debut at Belgrade Zoo

Raw: Rare Lion Cubs Make Debut at Belgrade Zoo

AP (Oct. 17, 2014) Two white lion cubs were born in Belgrade zoo three weeks ago. White lions are a rare mutation of a species found in South Africa and some cultures consider them divine. (Oct. 17) Video provided by AP
Powered by NewsLook.com
The Best Foods To Boost Your Mood

The Best Foods To Boost Your Mood

Buzz60 (Oct. 17, 2014) Feeling down? Reach for the refrigerator, not the medicine cabinet! TC Newman (@PurpleTCNewman) shares some of the best foods to boost your mood. Video provided by Buzz60
Powered by NewsLook.com
Sweet Times for Hard Cider Makers

Sweet Times for Hard Cider Makers

AP (Oct. 16, 2014) With hard cider making a hardcore comeback across the country, craft makers are trying to keep up with demand and apple growers are tapping a juicy new revenue stream. (Oct. 16) Video provided by AP
Powered by NewsLook.com
Meet Garfi the Angry Cat

Meet Garfi the Angry Cat

Buzz60 (Oct. 16, 2014) Garfi is one frowny, feisty feline - downright angry! Ko Im (@koimtv) introduces us to the latest animal celebrity taking over the Internet. You can follow more of Garfi's adventures on Twitter (@MeetGarfi) and Facebook (Garfi). Video provided by Buzz60
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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