Editing Blanket octopus

{{short description|Genus of cephalopods}}
{{Automatic taxobox
| name = Blanket octopus
| image = Pelagic octopus Tremoctopus.jpg
| image_caption = Adult female ''Tremoctopus''
| image_alt = Adult female Tremoctopus
| parent_authority = [[George Washington Tryon|Tryon]], 1879<ref name = WoRMS>{{cite web | url = http://www.marinespecies.org/aphia.php?p=taxdetails&id=138563 | title = ''Tremoctopus'' delle Chiaje, 1830 |access-date= 6 February 2018 | publisher = Flanders Marine Institute | author = Philippe Bouchet | year = 2013 | work = World Register of Marine Species | archive-url = https://web.archive.org/web/20190121233402/http://www.marinespecies.org/aphia.php?p=taxdetails&id=138563 | archive-date = 21 January 2019 | url-status = live }}</ref> 
| taxon = Tremoctopus
| authority = [[Stefano Delle Chiaje|Chiaje]], 1830<ref name = WoRMS/>
| type_species = ''[[Common blanket octopus|Tremoctopus violaceus]]''
| type_species_authority = delle Chiaje, 1830
| subdivision_ranks = Species
| subdivision = See text
| synonyms = ''Philonexis'' [[Alcide d'Orbigny|d'Orbigny]], 1835
| synonyms_ref = 
}}

'''''Tremoctopus''''' is a genus of [[pelagic]] [[cephalopods]], containing four species that occupy surface to mid-waters in subtropical and tropical oceans.<ref>{{Cite web|url=http://tolweb.org/Tremoctopus|title=Tremoctopus|website=tolweb.org|access-date=25 September 2019|archive-url=https://web.archive.org/web/20190917172619/http://www.tolweb.org/Tremoctopus/|archive-date=17 September 2019|url-status=live}}</ref> They are commonly known as '''blanket octopuses''', in reference to the long, transparent webs that connect the dorsal and dorsolateral [[cephalopod arm|arms]] of the adult females. The other arms are much shorter and lack webbing.

== Description ==
The [[common blanket octopus]] (''Tremoctopus violaceus'') exhibits one of the most extreme [[Sexual dimorphism#Reproductively advantageous|sexual size-dimorphism]] known in any animal near its size or larger.<ref name=NormanEtAl2002>{{cite journal |author1=Norman, M.D. |author2=Paul, D. |author3=Finn, J. |author4=Tregenza, T. |year=2002 |url=http://www.rsnz.org/publish/nzjmfr/2002/061.php |title=First encounter with a live male blanket octopus: The world's most sexually size-dimorphic large animal |archive-url=https://web.archive.org/web/20050119235052/http://www.rsnz.org/publish/nzjmfr/2002/061.php |archive-date=January 19, 2005 |df=dmy-all |journal=New Zealand Journal of Marine and Freshwater Research |volume=36 |issue=4 |pages=733–736|doi=10.1080/00288330.2002.9517126 |s2cid=15003259 |doi-access= }}</ref><ref>{{cite web |author=Pickrell, John |date=12 August 2003 |url=http://news.nationalgeographic.com/news/2003/02/0212_030212_walnutoctopus.html |title="Walnut-size" male octopus seen alive for first time |publisher=National Geographic Society |department=News |access-date=12 February 2005 |archive-url=https://web.archive.org/web/20050114090729/http://news.nationalgeographic.com/news/2003/02/0212_030212_walnutoctopus.html |archive-date=14 January 2005 |url-status=dead }}</ref> Females may reach {{convert|2|m|ft|abbr=on}} in length, whereas the males are 2.4&nbsp;cm (1 inch). The weight ratio is at least 10,000:1, and can probably reach as much as 40,000:1.<ref>{{Cite journal |last=Norman |first=M. D. |first2=Paul ,D. |first3=Finn, J. |last4=and Tregenza |first4=T. |date=2002-12-01 |title=First encounter with a live male blanket octopus: The world's most sexually size‐dimorphic large animal |url=https://www.tandfonline.com/doi/abs/10.1080/00288330.2002.9517126 |journal=New Zealand Journal of Marine and Freshwater Research |volume=36 |issue=4 |pages=733–736 |doi=10.1080/00288330.2002.9517126 |issn=0028-8330}}</ref> Adult Females carry a webbing between their arms, known as a "blanket". This webbing can be unfolded to make the female appear larger when threatened, deterring potential predators.<ref name="Blanket Octopus">{{Cite web |title=Blanket Octopus |url=https://www.barrierreef.org/the-reef/animals/blanket-octopus |access-date=2025-03-30 |website=Great Barrier Reef Foundation |language=en}}</ref>

== Reproduction ==
Male blanket octopuses have a large arm in a spherical pouch modified for mating, known as a [[hectocotylus]]. During mating, this arm is detached, and kept by the female in her mantle cavity until used for fertilisation. The male almost certainly dies shortly after mating.<ref name="NormanEtAl2002" /> There is competition between the males; multiple male arms have been found in the [[Mantle (mollusc)|mantle]] cavity of females.<ref name="NormanEtAl2002" /> The females carry more than 100,000 eggs attached to a sausage-shaped calcareous secretion held at the base of the dorsal arms and carried by the female until hatching.<ref>{{cite web |url=http://tolweb.org/accessory/Tremoctopus_Eggs,_etc.?acc_id=2416 |title=Tremoctopus Eggs, etc. |website=[[Tree of Life Web Project]] |access-date=25 September 2019 |archive-url=https://web.archive.org/web/20190916163149/http://www.tolweb.org/accessory/Tremoctopus_Eggs,_etc.?acc_id=2416 |archive-date=16 September 2019 |url-status=live }}</ref>

== Habitat and behavior ==
Blanket octopuses are immune to the venomous [[Portuguese man o' war]], whose tentacles the male and immature females rip off and use for offensive and defensive purposes.<ref>{{cite journal |last1=Jones |first1=E.C. |year=1963 |title=''Tremoctopus violaceus'' uses ''Physalia'' tentacles as weapons |journal=Science |volume=139 |issue=3556 |pages=764–766 |doi=10.1126/science.139.3556.764 |pmid=17829125 |bibcode=1963Sci...139..764J|s2cid=40186769 }}</ref> Like many other octopuses, the blanket octopus uses ink to intimidate potential predators.<ref>{{cite journal |last1=Thomas |first1=R.F. |year=1977 |title=Systematics, distribution, and biology of cephalopods of the genus ''Tremoctopus'' (Octopoda: Tremoctopodidae) |journal=Bulletin of Marine Science |volume=27 |issue=3 |pages=353–392}}</ref> Also, when threatened, the female unfurls her large net-like membranes that spread out and billow in the water, greatly increasing her apparent size.

Blanket octopuses usually live in coral reefs,<ref name="Blanket Octopus"/> where they hunt for food, which consists of small fish and jellyfish.<ref>{{Cite web |date=2018-12-07 |title=Blanket Octopus Facts |url=https://www.nationalgeographic.com/animals/invertebrates/facts/blanket-octopus?utm_source=chatgpt.com |access-date=2025-03-30 |website=Animals |language=en}}</ref> They also hide from their predators there, including larger fish and even whales. The risks these reefs face include coral bleaching and [[ocean acidification]]. Although this can be dangerous to the blanket octopus because it is their habitat, these creatures are nomadic meaning they can move around and find shelter elsewhere, and they also have the capability to adjust to varying temperatures within the ocean.{{citation needed|date=October 2022}}

==Species==
*''[[Tremoctopus gelatus]]'', gelatinous blanket octopus
*''[[Tremoctopus robsoni]]anus''
*''[[Tremoctopus gracilis]]'', [[palmate octopus]]
*''[[Common blanket octopus|Tremoctopus violaceus]]'', common blanket octopus or violet blanket octopus{{efn|Examination of [[mitochondrial DNA]] in specimens captured in the [[Mediterranean Sea]] found that they belonged to ''T. violaceus'' together with specimens from the [[Gulf of Mexico]].<ref>{{Cite journal |last1=Agus |first1=Blondine |last2=Carbonara |first2=Pierluigi |last3=Melis |first3=Riccardo |last4=Cannas |first4=Rita |last5=Carugati |first5=Laura |last6=Cera |first6=Jacopo |last7=Donnaloia |first7=Marilena |last8=Mulas |first8=Antonella |last9=Pais |first9=Antonio |last10=Ruiu |first10=Stefano |last11=Vinci |first11=Giuseppi |last12=Cuccu |first12=Danila |date=2022 |title=First Integrative Morphological and Genetic Characterization of ''Tremoctopus violaceussensu stricto'' in the Mediterranean Sea |journal=Animals |volume=12 |issue=1 |page=80 |doi=10.3390/ani12010080 |pmid=35011187 |pmc=8749848 |doi-access=free }}</ref>}}

{{multiple image
| align     = left
| footer    = Lower (left) and upper beaks of female ''[[Tremoctopus gracilis]]'' (54&nbsp;mm [[mantle length|ML]]) in lateral view<br/>{{3d glasses}}
| image1    = Tremoctopus gracilis lower beak (side view).jpg
| width1    = {{#expr: (200 * 1000 / 649) round 0}}
| image2    = Tremoctopus gracilis upper beak (side view).jpg
| width2    = 200
}}
{{Clear}}

==Notes==
{{notelist}}

==References==
{{Reflist|25em}}

==External links==
{{Spoken Wikipedia|Blanket_Octopus.ogg|date=2019-7-16}}
*{{Wikispecies-inline|Tremoctopididae}}
*{{Commons category-inline|Tremoctopus}}
*{{Wikibooks inline|Dichotomous Key|Tremoctopididae}}
*{{CephBase Genus|Tremoctopus}}
*{{cite web |url=http://tolweb.org/tree?group=Tremoctopus&contgroup=Argonautoid_families |title=Argonautoid families article – illustrates tentacle carrying |website=[[Tree of Life Web Project]]}}

{{Taxonbar|from=Q1417783|from2=Q18549893}}

[[Category:Octopuses]]
[[Category:Taxa named by Stefano delle Chiaje]]