Geographic Range
Mesonychoteuthis hamiltoni
occurs in the Southern Ocean from Antarctica to the southern tips of Africa, South
America, and New Zealand. This species’ range coincides with the Antarctic Circumpolar
Current.
- Biogeographic Regions
- australian
- antarctica
Habitat
Juveniles of
M. hamiltoni
swim in the upper 1000 m of the ocean and have not been found below 1000 m. The early
stages are concentrated beneath the surface layer in the upper zone of the warm deep
water, perhaps because at this depth biological activity is high resulting from spikes
in phytoplankton biomass. Because adult beaks have been found in the stomachs of sperm
whales, the adults must have reach depths of at least 2200 m.
- Habitat Regions
- polar
- saltwater or marine
- Aquatic Biomes
- abyssal
Physical Description
While no adults have been located or observed,
M. hamiltoni
may reach up to 14 m in length with a mantle length of 2-4 m. This species is the
largest known invertebrate. The eyes can measure up to 30 cm in diameter, possibly
the largest in the animal kingdom. These squid have the largest beaks of any squid,
along with 25 rotating hooks that are aligned in two rows at the ends of their tentacles.
- Other Physical Features
- ectothermic
- heterothermic
- bilateral symmetry
Development
Not much is known about M. hamiltoni development because no adult organisms have ever been captured or observed.
Reproduction
Upon dissection of a mature male adult, there seems to be no hectocotylus, which in
typical squids is the organ of sperm storage and transfer and is found at the end
of one of the male’s tentacles. Instead, it is speculated that
M. hamiltoni
males have penises.
Little is known about the reproductive behavior of
M. hamiltoni
because no specimens have been observed live. In general, many squids have precopulatory
rituals, and males seize females with their tentacles prior to mating. Fertilization
is likely internal.
- Key Reproductive Features
- fertilization
Little is known about the reproductive behavior of M. hamiltoni because no specimens have been observed live.
Lifespan/Longevity
No adult M. hamiltoni specimens have been discovered so the lifespan of the organism is currently unknown.
Behavior
Mesonychoteuthis hamiltoni
is thought to have a slow paced life because of its large size and low prey requirements.
- Key Behaviors
- natatorial
- motile
Communication and Perception
Mesonychoteuthis hamiltoni
is likely a visual predator due to its extremely large eye which can reach up to
about 30 cm in diameter.
- Other Communication Modes
- pheromones
Food Habits
Mesonychoteuthis hamiltoni
has low prey requirements and feeds on large fish including the Patagonian toothfish,
Dissostichus eleginoides
. One 5 kg toothfish may provide enough energy for a 500 kg squid to survive for up
to 200 days. As the squid grows older it moves into deeper and darker waters, possibly
to reduce the possibility of it being detected, and also to reduce predation pressure.
Mesonychoteuthis hamiltoni
is thought to be an ambush predator that depends on its hooks to catch prey. Because
of its size and probable energy intake, it most likely does not expend energy actively
chasing its prey.
- Animal Foods
- fish
Predation
The sperm whale,
Physeter catodon
is a known predator of
M. hamiltoni
.
Mesonychoteuthis hamiltoni
may prey on or fight with
P. catodon
.
Ecosystem Roles
Currently, little if anything is known about its distinct role in the ecosystem.
Economic Importance for Humans: Positive
Not much is known about this species and any benefits that it might have on humans yet.
Economic Importance for Humans: Negative
There are no known adverse affects of
M. hamiltoni
on humans. Because of its remote range, it is unlikely that this species has much
of a negative economic effect on humans.
Conservation Status
Not enough is known on colossal squid populations to determine its conservation status.
Additional Links
Contributors
Dan Ravaioli (author), Rutgers University, Tracy Youngster (author), Rutgers University, David V. Howe (editor), Rutgers University, Renee Mulcrone (editor), Special Projects.
- Australian
-
Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- Antarctica
-
lives on Antarctica, the southernmost continent which sits astride the southern pole.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- polar
-
the regions of the earth that surround the north and south poles, from the north pole to 60 degrees north and from the south pole to 60 degrees south.
- saltwater or marine
-
mainly lives in oceans, seas, or other bodies of salt water.
- abyssal
-
on or near the ocean floor in the deep ocean. Abyssal regions are characterized by complete lack of light, extremely high water pressure, low nutrient availability, and continuous cold (3 degrees C).
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- heterothermic
-
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- fertilization
-
union of egg and spermatozoan
- internal fertilization
-
fertilization takes place within the female's body
- natatorial
-
specialized for swimming
- motile
-
having the capacity to move from one place to another.
- visual
-
uses sight to communicate
- chemical
-
uses smells or other chemicals to communicate
- pheromones
-
chemicals released into air or water that are detected by and responded to by other animals of the same species
- visual
-
uses sight to communicate
- chemical
-
uses smells or other chemicals to communicate
- carnivore
-
an animal that mainly eats meat
- piscivore
-
an animal that mainly eats fish
References
Brusca, R., G. Brusca. 2003. Invertebrates . Sunderland, Massachusetts: Sinauer Associates, Inc..
Clarke, M., P. Prince. 1976. Cephalopod remains in regurgitations of black-browned and gray-headed albatrosses at South Georgia. British Antarctic Survey Bulletin , 54: 1-7. Accessed February 27, 2012 at http://www.antarctic.ac.uk/documents/bas_bulletins/bulletin54_02.pdf .
Evans, K., M. Hindell. 2004. The diets of sperm whales ( Physeter macrocephalus ) in southern Australian waters. ICES Journal of Marine Science , 61: 1313-1329. Accessed March 02, 2012 at http://icesjms.oxfordjournals.org/content/61/8/1313.full .
O'Shea, S., K. Bolstad. 2000. "Giant Squid and Colossal Squid Fact Sheet" (On-line). Accessed February 27, 2012 at http://www.tonmo.com/science/public/giantsquidfacts.php .
Rodhouse, P., M. Clarke. 1986. Distribution of the early-life phase of the Antarctic squid Galitheuthis glacialis in relation to the hydrology of the southern ocean in the sector 15° to 30° E. Marine Biology , 91: 353-357. Accessed February 27, 2012 at http://www.springerlink.com/content/rq77l5717244210q/fulltext.pdf .
Rosa, R., B. Seibel. 2010. Slow pace of life of the Antarctic colossal squid. Journal of the Marine Biological Association of the United Kingdom , 90: 1375-1378.