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Giant Squid: Life & Natural History
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Diversity
Squid Diversity
Squids come in a wide range of sizes, from smaller-than-your-thumb to the enormous giant squid.
Kim Moeller/Smithsonian Institution
The giant squid may be the biggest, but it’s not the only squid in the sea. Scientists estimate there are about 500 species of squid. Some are surprisingly tiny—only about 2.5 centimeters (1 inch) in length. Others are impressively large. There are three species of giant squid (Architeuthis), the largest of which may grow up to 16 meters (50 feet) long. And there are other large squid as well—including one known as the colossal squid (Mesonychoteuthis hamiltoni).
Despite these vast differences in size, all squids share certain features: long, cylindrical bodies, usually with eight arms and two long feeding tentacles; and two fins that help them balance and maneuver as they swim.
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Species Ecology
Reproduction: Once in a Lifetime
This squid embryo from a medium-sized squid—the arrow squid (Doryteuthis plei)—looks almost like a miniature adult.
©Clyde F.E. Roper
As far as researchers know, giant squid live less than five years. They reproduce only once during that short lifetime, so it’s a major event. Males use a modified arm to transfer sperm-filled tubes called spermatophores, which fertilize the female’s eggs. Females then release millions of tiny, transparent eggs into the water. Most are quickly snatched up as food by other marine animals. But a few survive…and grow up incredibly fast. Within just a few years, miniscule prey become giant marine predators.
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Both Predator and Prey
A giant squid engages in a struggle for survival with a sperm whale.
©Martin G. Roper
Giant squid are often depicted as monsters. The truth is that they are monstrous in size…but not in behavior. Like all squids, giant squid are aggressive predators. In the ocean’s dark depths, they hunt down fishes, crustaceans, squids, and other marine animals. But despite their huge size, giant squid are sometimes prey themselves to another huge marine animal. Scientists have found giant squid beaks, as well as other undigested pieces of giant squid, in the stomachs of sperm whales—the remains of a very large serving of calamari.
Anatomy of a Giant Squid
Giant squid have eight arms but use their two long feeding tentacles to seize prey.
Smithsonian Institution
A giant squid’s body may look pretty simple. But what it can do with that body! With their two long feeding tentacles, giant squid can snatch prey up to 10 meters (33 feet) away. Eight arms as thick as anacondas pull the prey to a sharp beak, where the prey is sliced into bite-sized pieces. The pieces must be very small because the giant squid’s esophagus passes through the brain before it reaches the stomach.
The head holds the world’s largest eyes and a complex brain. The main part of the body, or mantle, contains all the basic organs. And on the body’s underside is the funnel—an amazing multipurpose tool. The squid uses it to exhale, expel waste, lay eggs, squirt ink, and jet through the water.
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Evolution
Squids and Kin
Pacific cephalopods illustrate the wide diversity among this group of mollusks.
© 1996 (1), 1996 (2), 1996 (3), 1996 (4), 1998 (5), 1996 (6), 1996 (7), 1996 (8) R. E. Young, Hawaii Undersea Research Laboratory (2), Mark Norman (3), David Paul (4), Mark Norman (5), Thomas Burch (6), R. E. Young (7), R. E. Young (8)
Believe it or not, squids are closely related to snails, clams, and even slugs. All are mollusks and have soft, fleshy bodies. Squids belong to a particularly successful group of mollusks called the cephalopods, which have been around for about 500 million years.
The two main cephalopod groups that still exist today evolved around 470 million years ago. One group—the nautiluses—has an external shell. The other—which includes squids, cuttlefishes, and octopods—does not.
Shell or no shell, all cephalopods have well-developed brains and are very active, jet propelling themselves through the ocean. Most have ink sacs. And many can change skin color and texture in the blink of an eye.
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Comments
Cool!!!!!!!!
Submitted by Anonymous on Wed, 11/17/2010 - 8:46pm.WOW!!!! This website is full of info for my project!!!!!!!!!! Thanxs
Submitted by Anonymous on Sat, 06/18/2011 - 3:59pm.This website is riddled with both grammatical and spelling errors. Most unsatisfactory, good day.
Submitted by Anonymous on Sat, 07/09/2011 - 10:34pm.Amazing!!1 I lived in panama and have many times with squids, but i didn't know how amazing they are!!
Submitted by Anonymous on Sun, 07/17/2011 - 11:34am.this is intresting very!!!!!!!:):):):):):)
Submitted by Anonymous on Mon, 04/23/2012 - 12:05pm.comment_wrapper_curve
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