Colossal Squid
Encyclopedia
The colossal squid sometimes called the Antarctic or giant cranch squid, is believed to be the largest squid species in terms of mass
. It is the only known member of the genus
Mesonychoteuthis. Though it is known from only a few specimens, current estimates put its maximum size at 12–14 metres (39–46 feet) long, based on analysis of smaller and immature specimens, making it the largest known invertebrate
.
, whose arms
and tentacle
s only have suckers lined with small teeth, the colossal squid's limbs are also equipped with sharp hooks: some swivelling, others three-pointed. Its body is wider and stouter, and therefore heavier, than that of the giant squid. Colossal squids are believed to have longer mantles
than giant squids, although their tentacles are shorter.
The squid exhibits abyssal gigantism
. The beak of Mesonychoteuthis hamiltoni is the largest known of any squid, exceeding that of Architeuthis (giant squid) in size and in robustness. The colossal squid also has the largest eyes documented in the animal kingdom.
.
, large fish
like the Patagonian toothfish
, and other squid in the deep ocean
using bioluminescence
. The colossal squid is thought to have a slow metabolic rate, needing only around 30 g of prey daily. Estimates of its energetic demands suggest that it is a slow-moving ambush predator
, using its large eyes primarily for predator detection rather than active hunting.
Based on capture depths of a few specimens, and beaks found in sperm whale
stomachs, the adult colossal squid ranges at least to a depth of 2.2 kilometres (7,217.8 ft), and juveniles can go as deep as 1 kilometres (3,280.8 ft). It is believed to be sexually dimorphic, with mature females generally being much larger than mature males, as is common in many species of invertebrates.
The squid's method of reproduction has not been observed, although some data on their reproduction can be inferred from anatomy. Since males lack an organ called a hectocotylus
(an arm used in other cephalopod
s to transfer a spermatophore
to the female), they probably use a penis
instead, which would be used to directly implant sperm into females.
Many sperm whales carry scars on their backs believed to be caused by the hooks of colossal squid. Colossal squid are a major prey item for Antarctic sperm whales feeding in the Southern Ocean; 14% of the squid beaks found in the stomachs of these sperm whales are those of the colossal squid, which indicates that colossal squid make up 77% of the biomass consumed by these whales. Many other animals also feed on this squid, including beaked whale
s (such as the bottlenose whale
s), pilot whale
s, southern elephant seal
s, Patagonian toothfish
, sleeper sharks (Somniosus cf. microcephalus), and albatross
es (e.g., the Wandering
and Sooty albatross
es). However, beaks from mature adults have only been recovered from those animals large enough to take such prey (i.e., sperm whales and sleeper sharks
), while the remaining predators are limited to eating juveniles or young adults.
On February 22, 2007, it was announced by authorities in New Zealand that the largest known colossal squid had been captured. The specimen weighed 495 kg (1,091 lb) and was initially estimated to measure 10 m (33 ft) in total length. Fishermen on the vessel San Aspiring, owned by the Sanford seafood company, caught the animal in the freezing Antarctic waters of the Ross Sea
. It was brought to the surface as it fed on an Antarctic toothfish that had been caught off a long line
. It would not let go of its prey and could not be removed from the line by the fishermen, so they decided to catch it instead. They managed to envelop it in a net, hauled it aboard and froze it. The specimen eclipsed the previous largest find in 2003 by about 195 kilograms (430 lb), although it is still considerably smaller than some estimates have predicted. The specimen was frozen in a cubic metre of water and transported to the Museum of New Zealand Te Papa Tongarewa
, New Zealand's national museum. Media reports suggested that scientists at the museum were considering using a giant microwave to defrost the squid because defrosting the squid at room temperatures would take days and it would be likely for the outside to rot while the core remained frozen. However, they later opted for the more conventional approach of thawing the specimen in a bath of salt water. After thawing, the squid measured only 4.2 m (14 ft) in total length, with the tentacles having shrunk significantly. Although initially thought to be a male, closer inspection of the specimen showed it to be a female.
under the direction of senior biologist Chris Paulin, with technician Mark Fenwick, Dutch marine biologist and toxicologist Olaf Blaauw, AUT biologist Dr Steve O'Shea
, Dr Tsunemi Kubodera
, and AUT biologist Kat Bolstad.
Parts of the specimen have been examined:
The Museum of New Zealand Te Papa Tongarewa
is displaying this specimen in an exhibition which opened on December 13, 2008. A website on the squid specimen is also available.
Cephalopod size
Size has been one of the most interesting aspects of cephalopod science to the general public. This article lists the largest cephalopods from various groups, sorted in order of mantle length, total length, weight, and shell diameter...
. It is the only known member of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Mesonychoteuthis. Though it is known from only a few specimens, current estimates put its maximum size at 12–14 metres (39–46 feet) long, based on analysis of smaller and immature specimens, making it the largest known invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
.
Morphology
Unlike the giant squidGiant squid
The giant squid is a deep-ocean dwelling squid in the family Architeuthidae, represented by as many as eight species...
, whose arms
Cephalopod arm
A cephalopod arm is distinct from a tentacle, though the terms are often used interchangeably.Generally, cephalopod arms have suckers along most of their length, as opposed to tentacles, which have suckers only near their ends. Octopuses have eight arms and no tentacles, while squid and cuttlefish...
and tentacle
Tentacle
A tentacle or bothrium is one of usually two or more elongated flexible organs present in animals, especially invertebrates. The term may also refer to the hairs of the leaves of some insectivorous plants. Usually, tentacles are used for feeding, feeling and grasping. Anatomically, they work like...
s only have suckers lined with small teeth, the colossal squid's limbs are also equipped with sharp hooks: some swivelling, others three-pointed. Its body is wider and stouter, and therefore heavier, than that of the giant squid. Colossal squids are believed to have longer mantles
Mantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...
than giant squids, although their tentacles are shorter.
The squid exhibits abyssal gigantism
Deep-sea gigantism
In zoology, deep-sea gigantism, also known as abyssal gigantism, is the tendency for species of crustaceans, invertebrates and other deep-sea-dwelling animals to display a larger size than their shallow-water counterparts...
. The beak of Mesonychoteuthis hamiltoni is the largest known of any squid, exceeding that of Architeuthis (giant squid) in size and in robustness. The colossal squid also has the largest eyes documented in the animal kingdom.
Distribution
The squid's known range extends thousands of kilometres northward from Antarctica to southern South America, southern South Africa, and the southern tip of New Zealand, making it primarily an inhabitant of the entire circumantarctic Southern OceanSouthern Ocean
The Southern Ocean comprises the southernmost waters of the World Ocean, generally taken to be south of 60°S latitude and encircling Antarctica. It is usually regarded as the fourth-largest of the five principal oceanic divisions...
.
Ecology and life history
Little is known about the life of this creature, but it is believed to feed on prey such as chaetognathaChaetognatha
Chaetognatha, meaning hair-jaws, and commonly known as arrow worms, are a phylum of predatory marine worms that are a major component of plankton worldwide. About 20% of the known species are benthic, that is belonging to the lowest zone of the ocean, or benthic zone, and can attach to algae and...
, large fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
like the Patagonian toothfish
Patagonian toothfish
The Patagonian toothfish, Dissostichus eleginoides , is a fish found in the cold, temperate waters of the southern Atlantic, southern Pacific, Indian, and Southern Oceans on seamounts and continental shelves around most sub-Antarctic islands.A close relative, the Antarctic toothfish , is found...
, and other squid in the deep ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
using bioluminescence
Bioluminescence
Bioluminescence is the production and emission of light by a living organism. Its name is a hybrid word, originating from the Greek bios for "living" and the Latin lumen "light". Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in...
. The colossal squid is thought to have a slow metabolic rate, needing only around 30 g of prey daily. Estimates of its energetic demands suggest that it is a slow-moving ambush predator
Ambush predator
Ambush predators or sit-and-wait predators are carnivorous animals that capture prey by stealth or cunning, not by speed or necessarily by strength. These organisms usually hide motionless and wait for prey to come within striking distance. They are often camouflaged, and may be solitary...
, using its large eyes primarily for predator detection rather than active hunting.
Based on capture depths of a few specimens, and beaks found in sperm whale
Sperm Whale
The sperm whale, Physeter macrocephalus, is a marine mammal species, order Cetacea, a toothed whale having the largest brain of any animal. The name comes from the milky-white waxy substance, spermaceti, found in the animal's head. The sperm whale is the only living member of genus Physeter...
stomachs, the adult colossal squid ranges at least to a depth of 2.2 kilometres (7,217.8 ft), and juveniles can go as deep as 1 kilometres (3,280.8 ft). It is believed to be sexually dimorphic, with mature females generally being much larger than mature males, as is common in many species of invertebrates.
The squid's method of reproduction has not been observed, although some data on their reproduction can be inferred from anatomy. Since males lack an organ called a hectocotylus
Hectocotylus
A hectocotylus is one of the arms of the male of most kinds of cephalopods that is modified in various ways to effect the fertilization of the female's eggs. It is a specialized, extended muscular hydrostat used to store spermatophores, the male gametophore...
(an arm used in other cephalopod
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
s to transfer a spermatophore
Spermatophore
A spermatophore or sperm ampulla is a capsule or mass created by males of various animal species, containing spermatozoa and transferred in entirety to the female's ovipore during copulation...
to the female), they probably use a penis
Penis
The penis is a biological feature of male animals including both vertebrates and invertebrates...
instead, which would be used to directly implant sperm into females.
Many sperm whales carry scars on their backs believed to be caused by the hooks of colossal squid. Colossal squid are a major prey item for Antarctic sperm whales feeding in the Southern Ocean; 14% of the squid beaks found in the stomachs of these sperm whales are those of the colossal squid, which indicates that colossal squid make up 77% of the biomass consumed by these whales. Many other animals also feed on this squid, including beaked whale
Beaked whale
Beaked whales are 21 species of toothed whales, members of the family Ziphiidae, are notable for their elongated beaks. Beaked whales are one of the world's most extreme divers. They can dive for long periods—20 to 30 minutes is common, and 85 minute dives have been recorded—and to...
s (such as the bottlenose whale
Bottlenose whale
The Northern bottlenose whale is a species of the ziphiid family, one of two members of the Hyperoodon genus. The northern bottlenose was hunted heavily by Norway and Britain in the 19th and early 20th centuries...
s), pilot whale
Pilot whale
Pilot whales are cetaceans belonging to the genus Globicephala. There are two extant species, the long-finned pilot whale and the short-finned pilot whale . The two are not readily distinguished at sea and analysis of the skulls is the best way to tell the difference between them...
s, southern elephant seal
Southern Elephant Seal
The Southern Elephant Seal is one of the two extant species of elephant seal. It is both the most massive pinniped and member of the order Carnivora living today...
s, Patagonian toothfish
Patagonian toothfish
The Patagonian toothfish, Dissostichus eleginoides , is a fish found in the cold, temperate waters of the southern Atlantic, southern Pacific, Indian, and Southern Oceans on seamounts and continental shelves around most sub-Antarctic islands.A close relative, the Antarctic toothfish , is found...
, sleeper sharks (Somniosus cf. microcephalus), and albatross
Albatross
Albatrosses, of the biological family Diomedeidae, are large seabirds allied to the procellariids, storm-petrels and diving-petrels in the order Procellariiformes . They range widely in the Southern Ocean and the North Pacific...
es (e.g., the Wandering
Wandering Albatross
The Wandering Albatross, Snowy Albatross or White-winged Albatross, Diomedea exulans, is a large seabird from the family Diomedeidae, which has a circumpolar range in the Southern Ocean. It was the first species of albatross to be described, and was long considered the same species as the Tristan...
and Sooty albatross
Sooty albatross
The sooty albatrosses are small albatrosses from the genus Phoebetria. There are two species, the Sooty Albatross, Phoebetria fusca, and the Light-mantled Albatross, Phoebetria palpebrata...
es). However, beaks from mature adults have only been recovered from those animals large enough to take such prey (i.e., sperm whales and sleeper sharks
Somniosidae
Somniosidae is a family of sharks in the order Squaliformes, commonly known as sleeper sharks.-Genera:* Centroscymnus Barbosa du Bocage & Brito Capello, 1864...
), while the remaining predators are limited to eating juveniles or young adults.
Timeline
- 1925 – Species was first discovered in the form of two tentacles found in the stomach of a sperm whaleSperm WhaleThe sperm whale, Physeter macrocephalus, is a marine mammal species, order Cetacea, a toothed whale having the largest brain of any animal. The name comes from the milky-white waxy substance, spermaceti, found in the animal's head. The sperm whale is the only living member of genus Physeter...
. - 1981 – A Russian trawler in the Ross SeaRoss SeaThe Ross Sea is a deep bay of the Southern Ocean in Antarctica between Victoria Land and Marie Byrd Land.-Description:The Ross Sea was discovered by James Ross in 1841. In the west of the Ross Sea is Ross Island with the Mt. Erebus volcano, in the east Roosevelt Island. The southern part is covered...
, off the coast of Antarctica, caught a large squid with a total length of 4 metres (13 ft), which was later identified as an immature female of Mesonychoteuthis hamiltoni. - 2003 – A complete specimen of a subadult female was found near the surface with a total length of 6 m (20 ft) and a mantle length of 2.5 m (8 ft).
- 2005 – A specimen was captured at a depth of 1625 m while taking a toothfish from a longlineLong-line fishingLongline fishing is a commercial fishing technique. It uses a long line, called the main line, with baited hooks attached at intervals by means of branch lines called "snoods". A snood is a short length of line, attached to the main line using a clip or swivel, with the hook at the other end....
off South Georgia Island. Although the mantle was not brought aboard, the mantle length was estimated at over 2.5 m, and the tentacles measured 230 cm. The animal is thought to have weighed between 150 and 200 kg. - 2007 – The largest recorded specimen was captured by a New Zealand fishing boat off Antarctica. It was initially estimated to measure 10 m (33 ft) in length and weigh 450 kg (992 lb). The squid was taken back to New Zealand for scientific study. A study on the specimen later showed that its actual weight was 495 kg (1,091 lb), but that it only measured 4.2 m (14 ft) in total length as a result of the tentacles shrinking post mortem.
Largest known specimen
Ross Sea
The Ross Sea is a deep bay of the Southern Ocean in Antarctica between Victoria Land and Marie Byrd Land.-Description:The Ross Sea was discovered by James Ross in 1841. In the west of the Ross Sea is Ross Island with the Mt. Erebus volcano, in the east Roosevelt Island. The southern part is covered...
. It was brought to the surface as it fed on an Antarctic toothfish that had been caught off a long line
Long-line fishing
Longline fishing is a commercial fishing technique. It uses a long line, called the main line, with baited hooks attached at intervals by means of branch lines called "snoods". A snood is a short length of line, attached to the main line using a clip or swivel, with the hook at the other end....
. It would not let go of its prey and could not be removed from the line by the fishermen, so they decided to catch it instead. They managed to envelop it in a net, hauled it aboard and froze it. The specimen eclipsed the previous largest find in 2003 by about 195 kilograms (430 lb), although it is still considerably smaller than some estimates have predicted. The specimen was frozen in a cubic metre of water and transported to the Museum of New Zealand Te Papa Tongarewa
Museum of New Zealand Te Papa Tongarewa
The Museum of New Zealand Te Papa Tongarewa is the national museum and art gallery of New Zealand, located in Wellington. It is branded and commonly known as Te Papa and Our Place; "Te Papa Tongarewa" is broadly translatable as "the place of treasures of this land".The museum's principles...
, New Zealand's national museum. Media reports suggested that scientists at the museum were considering using a giant microwave to defrost the squid because defrosting the squid at room temperatures would take days and it would be likely for the outside to rot while the core remained frozen. However, they later opted for the more conventional approach of thawing the specimen in a bath of salt water. After thawing, the squid measured only 4.2 m (14 ft) in total length, with the tentacles having shrunk significantly. Although initially thought to be a male, closer inspection of the specimen showed it to be a female.
Defrosting and dissection, April–May 2008
Thawing and dissection of the specimen took place at the Museum of New Zealand Te Papa TongarewaMuseum of New Zealand Te Papa Tongarewa
The Museum of New Zealand Te Papa Tongarewa is the national museum and art gallery of New Zealand, located in Wellington. It is branded and commonly known as Te Papa and Our Place; "Te Papa Tongarewa" is broadly translatable as "the place of treasures of this land".The museum's principles...
under the direction of senior biologist Chris Paulin, with technician Mark Fenwick, Dutch marine biologist and toxicologist Olaf Blaauw, AUT biologist Dr Steve O'Shea
Steve O'Shea
Steve O'Shea is a marine biologist and environmentalist known for his research on giant squid. O'Shea began work with the giant squid whilst working for the National Institute of Water and Atmospheric Research in New Zealand in 1996....
, Dr Tsunemi Kubodera
Tsunemi Kubodera
is a Japanese zoologist with the National Science Museum of Japan. On September 30, 2004, Kubodera and his team became the first people to photograph a live giant squid in its natural habitat...
, and AUT biologist Kat Bolstad.
Parts of the specimen have been examined:
- The beak is considerably smaller than some found in the stomachs of sperm whales, suggesting there are colossal squid much larger than this one.
- The eye is 27 cm (10.63 in) wide, with a lens 12 cm across. This is the largest eye of any known animal. These measurements are of the partly collapsed specimen: when living the eye was probably 30 to 40 cm (12 to 16 in) across.
- Inspection of the specimen with an endoscope revealed ovariesOvaryThe ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...
containing thousands of eggs.
Exhibition
Museum of New Zealand Te Papa Tongarewa
The Museum of New Zealand Te Papa Tongarewa is the national museum and art gallery of New Zealand, located in Wellington. It is branded and commonly known as Te Papa and Our Place; "Te Papa Tongarewa" is broadly translatable as "the place of treasures of this land".The museum's principles...
is displaying this specimen in an exhibition which opened on December 13, 2008. A website on the squid specimen is also available.
Further reading
Klumov, S.K. & V.L. Yukhov 1975. Mesonychoteuthis hamiltoni Robson, 1925 (Cephalopoda, Oegopsida). Antarktika Doklady Komission 14: 159–189. [English translation: TT 81-59176, Al Ahram Center for Scientific Translations]- McSweeny, E.S. 1970. Description of the juvenile form of the Antarctic squid Mesonychoteuthis hamiltoni Robson. Malacologia 10: 323–332.
- Rodhouse, P.G. & M.R. Clarke 1985. Growth and distribution of young Mesonychoteuthis hamiltoni Robson (Mollusca: Cephalopoda): an Antarctic squid. Vie Milieu 35(3–4): 223–230.
External links
- Tree of Life web project: Mesonychoteuthis hamiltoni
- Museum of New Zealand Te Papa Tongarewa (Te Papa) Colossal Squid Specimen Information
- Tonmo.com: Giant Squid and Colossal Squid Fact Sheet
- New Zealand Herald: Fishermen haul in world's biggest squid
- National Geographic News: Colossal Squid Caught off Antarctica
- National Geographic News: Colossal Squid Revealed in First In-Depth Look
- USA Today: Colossal Squid Caught in Antarctic Waters
- BBC: Super squid surfaces in Antarctic
- MarineBio: Mesonychoteuthis hamiltoni