Squid
By Alonzo

Squids are a marine animal that have eight to ten limbs coming out of their mouth! Squids have suckers attached to their arms and tentacles. They do not have backbones which means they are invertebrates.  Squids can be found in oceans all around the globe.

Many researchers believe that squid change colors as a form of communication.  Scientists who have studied squids' color change noticed that it is very purposeful and not only camouflage as some believe.  Squids have been found to be color blind, so it is believed that the contrast of the pattern, more than the color, is used to communicate between squid.  Squids sometimes change color and wave their arms to attract females and to scare off rivals.

One type of squid, the Humboldt, have been seen flashing like strobe lights at each other usually when they are hunting or feeding.  This has appeared to be how they communicate with each other.

When squids have been observed in groups, it appears they have cooperative hunting behaviors which shows that they are very smart animals.  They have such a large brain that they are believed to be one of the smartest animals in the world.

One type of squid, the Carribean reef squid, lives in a group of 20 or more inside reefs.  Carribean reef squid have been seen communicating to each other by changing their skin patterns and colors.  Squid are able to change colors, because they have skin cells that contain a colored pigment. The squid will also vary their postures, and turn on and off their skin patterns and colors as a form of communication.  

Squids belong to the scientific class Cephalopoda.  They are shaped like torpedoes, have a  distinct head, a mantle (body), eight tentacles with suckers, and two paired tentacles used for capturing and eating prey.  The suckers on their arms are 2-5 centimeters wide and have a double ring of sharp teeth. Squid also have two fins that are used to steer them through the water.  A squid's mouth looks like a parrot's beak.

Squids range in length from 3/4 of an inch to over 70 feet. Since a squid has no bones, it has a pen "reduced shell" inside it's body. They have two gills called ctenidia and two gill hearts.  

There are many different kinds of squid. A loligo squid can change its color from red to green to semi-transparent.  A vampire squid has its own light to help its large red eyes to see.  The vampire squid is only 11 inches long. There is webbed skin between the vampire squids arms.  The vampire squid is deep purple or black.  An adult giant squid is usually 60 feet long (18 meters) and can weigh up to 1000 pounds.  Another very large squid is the humboldt squid which can be up to 10 feet long. The Carribean reef squid, as well as all other squid, have a brain  controlled chromatophore system.  This system allows them to change color and position within 30 milliseconds.  Squid also have iridophores and leucophores, which are used in addition to the chromatophores.  The iridophores and leucophres reflect light differently. 

Squids come in many sizes and shapes.  On a lolling squid, there are eight 6 inch long arms with two rows of suckers and hooks located below its eyes.  In addition to the 8 short arms, the lolling squid has two one foot long arms that help it catch its prey.  The entire length of the loligo squid is only 1 1/2 to 2 feet long.  A more common breed of squid, the Carribean reef squid, is only about 1 foot long. The long arm squid has ten long arms that bend.  It can be up to 10-20 feet in length.  This squid has two huge fins that flap when it swims. The firefly squid is 2 inches long as compared to the pygmy squid which is about as long as a honey bee.

Squids are found in all the seas and at many different depths.  The loligo squid lives on the western coast of North America.  It's basic habitat is either near the surface or at great depths.  Vampire squids live is the Pacific and Atlantic Oceans.  They swim up to 15,840 feet below the surface of the ocean. The giant squid lives from 1000-3000 feet below sea level.  The giant squid eats its prey by enveloping its prey in a ball of tentacles.  The giant squid must be in constant motion to maintain its buoyancy, or it would sink to the bottom of the ocean. The Carribean reef squid lives in the reefs of the Carribean sea. The longfin inshore squid lives in the Atlantic Ocean from Newfoundland to Venezuela.   The veined squid lives in the Eastern Atlantic Ocean and the Mediterranean Sea. The Humboldt squid lives in huge numbers along the west coast of North American including the Gulf of Mexico and Monterrey Bay. One time 1500 Humboldt squid washed up on Newport Beach.  

Many people like to eat squid.  In a good year, a Mexican fisherman could catch up to 100,000 tons of Humboldt squid.

When a squid mates, it gathers in shoals (schools).  A loligo squid mates by the male squid transferring a special sac called a spermataphore to the females mantle cavity using a special arm called a hectocotylus.  The female then lays 20 sacs of 200 - 300 eggs.  20% of the eggs die before hatching and 50% of the newborn squid are devoured by predators during the first week of their lives.  The female squid does not care for her eggs after they are laid.  The female loses strength and dies after she deposits her eggs.

• A squid has three hearts.

• Squids have blue blood.

• Once a diver was snorkeling and a squid came up to him and tapped on his hand with its tentacle.  The diver thought he was going to be lunch, but the squid was just saying "hi."

• At one time, squid were not believed to be real but rather the subject of sailors' tall tales.  

• A giant squid can weigh over 100 pounds!

• A pygmy squid is only as long as a honeybee.

• Squid only live a few months to a few years.

• There have been very few squid attacks on people. 

Did you know divers wear protective gear and armored breathing gear to protect themselves from squids?  When diving with squid, a diver usually never sees the same behavior twice.  Researchers believe that its impossible to predict the behavior of a squid in any situation. Like sharks, squid have been seen going wild in the water when there is blood, especially blood from another squid.  Hunters and researchers actually hang dead squid over the sides of their boats to attract squid to study them.

Friends of the squid include the gulper eel, the tripod fish, the snipe eel, and the abyssal anenome.  They live at similar depths in the ocean. Cephalods (a mollusk with tentacles and a hard beak such as octupus, squid and cuttlefish) are the only mollusks that go through a period of sleep similar to that of mammals.

Books

Byrne, R.A., U. Griebel, J.B. Wood and J.A. Mather.  (2003)  "Squid Say it With Skin:  A Graphic Model for Skin Displays in Caribbean Reef Squid. (Sepioteuthis Sepioidea).  In:  Warnke, K., H. Keupp, Boletzky, S. v,.eds.  Coleiod Cephlapods Through Time.  Berliner Palaobiol. 

Cousteau, Jacques-Yves and Philippe Diole.  Octopus and Squid the Soft Intelligence.  Garden City:  Doubleday and Company, Inc.,  1973.  

Ellis, Richard.  The Search for the Giant Squid.  New York:  Lyons Press, 1998.

Garcia, Eulalia.  Secrets of the Animal World:  Giant Squid Monsters of the Deep.  Milwaukee:  Gareth Stevens Publishing, 1997.

Martin, James.  Tentacles:  The Amazing World of Octopus, Squid and their Relatives.  New York:  Crown Publishers Inc.,  1993.

Rhodes, Mary JO and David Hall.  Octopuses and Squids.  New York:  Children's Press,  2005.

Online Resources

"Giant Squid."  World Book Online Reference Center.  3 January 2006 <http://www.worldbookonline.com/wb/Article?id=ar223540&st=Squid>.

"Japanese Firefly Squid."  Searchasaurus.  31 January 2006.  <http://sasweb1.epnet.com/print.asp?tb=0&_ug=sid+52A21F24%2D50D2%2D4748%2DB... >. (Link no longer available)

"Loligo Squid."  Searchasaurus.  3 January 2006.   <http://sasweb1.epnet.com/citation.asp?tb=0&_ug=sid+8C040ECE%2D308E%2D44E5%2D... >.(Link no longer available)

Miller, Laura.  In Search of the Giant Squid.  4 January 2006.  <http://www.salon.com/dec96/squid961202.html>.

Owen, James.  "Holy Squid!  Photos Offer First Glimpse of Live Deep-sea Giant."  National Geographic News.  27 September 2005.  <http://news.nationalgeographic.com/news/2005/09/0927_050927_giant_squid.html> .

"Real Sea Monsters: The Vicious Giant Dosidicus Gigas, The Humboldt Squid, Seems to be Finding a New Home Right off Our Shores."  Monterey County Weekly.  10 March 2005.  <http://www.montereycountyweekly.com/issues/Issue.03-10-2005/cover/Article.cover_story>.

"Squid."  Wikipedia.  11 January 2006.  <http://en.wikipedia.org/wiki/Squid> .

"Squid."  World Book Online Reference Center.  3 January 2006.  <http://www.worldbookonline.com/wb/Article?id+ar527540&st=Squid> .

"Vampire Squid."  Searchasaurus.  3 January 2006.  <http://sasweb1epnet.com/citation.asp?tb=0&_ug=sid+8C040ECE%2D308E%2D44E5%2D...>. (Link no longer available)

Images

Copyrighted images of red squid, squid diagram and squid picture from  "Ocean Color Web" <http://seawifs.gsfc.nasa.gov/> Permission granted from Gene Carl Feldman <gene.c.feldman@nasa.gov> Personal email April 6, 2006.  

Photograph of packaged squid has been released into the public domain from Wikipedia, the Free Encyclopedia.  <http://en.wikipedia.org/wiki/Main_Page>.

Permission to use photograph of Carribean reef squid  is granted  under the terms of the GNU Free Documentation License from Wikipedia, the Free Encyclopedia.  <http://en.wikipedia.org/wiki/Main_Page>.

Copyrighted image of squid on top from "Microsoft Office Online" <http://office.microsoft.com/clipart/default.aspx?lc=en-us&cag=1>
February, 2006. Clip art available only to licensed users for non-commercial purposes.