Giant squid
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Architeuthis dux |
Giant squid are marine mollusks of the class Cephalopoda, represented by the eight species of the genus Architeuthis. They are deep-ocean dwellers that can grow to tremendous size: recent estimates put the maximum size at 10 m (33 ft) for males and 13 m (43 ft) for females from caudal fin to the tip of the two long tentacles. The mantle length, though, is only about 2 m (7 ft) in length (more for females, less for males), and the length of the squid excluding its tentacles is about 5 m (16 ft). However, there are reported claims of specimens of up to 20 m (66 ft), but none have been scientifically documented. The first real evidence of the existence of a giant squid was in 1873 when one attacked a minister and a young boy in a dory in Bell Island, Newfoundland. A 17 m (55 ft) giant squid specimen washed ashore in Glover's Harbour, Newfoundland on November 2, 1878.
A_piece_of_sperm_whale_skin_with_Giant_Squid_sucker_scars.JPG
Despite their great length, giant squid are not particularly heavy when compared to their chief predator, the Sperm Whale, because the majority of their length is taken up by their eight arms and two tentacles. The weights of recovered specimens have been measured in hundreds, rather than thousands, of pounds. Though an adult has never been seen alive, post-larval juveniles have been discovered in surface waters off New Zealand, and there are plans to capture more such juveniles and maintain them in an aquarium in an attempt to learn more about the creature's biology and habits.
The reproductive cycle of the giant squid is still a great mystery, but what has been learned so far is both bizarre and fascinating; male giant squid are equipped with a prehensile spermataphore-depositing tube of over three feet (90 cm) in length, which extends from inside the animal's mantle and apparently is used to inject sperm-containing packets into the female squid's arms – how exactly the sperm then is transferred to the egg mass is a matter of much debate, but the recent recovery in Tasmania of a female specimen having a small subsidiary tendril attached to the base of each of its eight arms could be a vital clue in the solution of this enigma.
Giant squid possess the largest eyes of any living creature, over 30 cm (one foot) in diameter, and their arms are equipped with hundreds of suction cups in total; each is mounted on an individual "stalk" and equipped around its circumference with a ring of sharp teeth to aid the creature in capturing its prey by firmly attaching itself to it both by suction and perforation. The size of these suction cups can vary from 2 to 5 cm in diameter (one to two inches), and it is not uncommon to find their circular scars on the head area of sperm whales that have fed – or attempted to feed – upon giant squid. The only other known predator of the giant squid is the sleeper shark, found off Antarctica. Because sperm whales are skilled at locating giant squid, scientists have attempted to conduct in-depth observations of sperm whales in order to study squid.
One of the more unusual aspects of giant squid (as well as some other species of large squid) is their reliance upon the light weight of ammonia in relation to seawater to maintain neutral buoyancy in their natural environment, as they lack the gas-filled swim bladder that fish use for this function; instead, they use ammonia (in the form of ammonium chloride) in the fluid of their flesh throughout their bodies. This makes the giant squid unfit for human consumption, although sperm whales seem to be attracted by (or at least tolerant of) its taste.
Like all cephalopods they use special organs called statocysts to sense their orientation and motion in the water. The age of giant squids can be estimated by "growth rings" in the statocyst's "statolyth" much like counting tree rings. Much of what is known about these animals come from estimates based on these, and from beaks found in sperm whale stomachs.
The search for a live Architeuthis specimen includes attempts to find live young, including larvae. Larval Architeuthis closely resemble larvae of Nototodarus and Moroteuthis, with distinctive characteristics being the shape of the mantle attachment by the head, the tentacle suckers, and the beaks. Approximately 65 specimens, one-fifth of all the giant squid ever found, have been found in the waters off Newfoundland; the last in December 2004.
Recently, a possibly even more massive squid, the little known Colossal Squid Mesonychoteuthis hamiltoni, has been described in more detail due to a new specimen being found. It is an inhabitant of Antarctic waters, and unlike the giant squid, relies upon both claw-like hooks and suction cups on its arms and tentacles to capture prey. Although its body may be of greater size than the giant squid, its tentacles appear to be considerably shorter in length; it is also believed to be responsible for scars on the backs of sperm whales, through the use of hooks on its tentacles.
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Giant squid in culture
Tales of giant squid have been common among mariners since ancient times, and may have led to the Norwegian legend of the kraken, a tentacled sea monster as large as an island capable of engulfing and sinking any ship. However, it is thought to be impossible for a giant squid to lift its tentacles from the water. Eyewitness accounts of other sea monsters like the sea serpent are also thought to be mistaken interpretations of giant squid.
- James Bond fights a giant squid in Ian Fleming's book, "Dr. No"
- A giant squid also dwells in the lake at Hogwarts, in the Harry Potter Series of Books.
Species
- Atlantic Giant Squid, Architeuthis dux
- Architeuthis hartingii
- Architeuthis japonica
- Architeuthis kirkii
- Architeuthis martensi
- Architeuthis physeteris
- Southern Giant Squid, Architeuthis sanctipauli
- Architeuthis stockii
References
- Ellis, R. (1998) The Search for the Giant Squid. Lyons Press. London.
- National Geographic Video: "Sea Monsters"
External links
- CephBase entry for Architeuthis (http://www.cephbase.utmb.edu/spdb/genusgroup.cfm?Genus=Architeuthis)
- TONMO.com's fact sheet for giant and colossal squids (http://www.tonmo.com/science/public/giantsquidfacts.php)
- Encounters with Giant Squid. (http://unmuseum.mus.pa.us/squid.htm)
- 15 January, 2003, Giant squid 'attacks French boat' (http://news.bbc.co.uk/1/hi/sci/tech/2661691.stm) Citat: "..."I saw a tentacle through a porthole," Olivier de Kersauson said from his boat. "It was thicker than my leg and it was really pulling the boat hard."..."
- Live Giant Squid stranded in Japan in 2002. (http://www.pref.kyoto.jp/kaiyo/2-topicnews/news/2002/02-02-01/mega-squid/mega-squid-01.html)
- Additional photos of stranded squid (http://www.pref.kyoto.jp/kaiyo/2-topicnews/news/2002/02-02-01/mega-squid/mega-squid-02.html)
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