{{Short description|Species of octopus}} {{Speciesbox | image = Octopus australis.jpg | status = LC | status_system = IUCN3.1 | status_ref = <ref>{{cite iucn |author=Allcock, L. |author2=Allen, G. |author3=Headlam, J. |year=2018 |title=''Octopus australis'' |volume=2018 |article-number=e.T163388A1004127 |doi=10.2305/IUCN.UK.2018-2.RLTS.T163388A1004127.en |access-date=12 September 2025}}</ref> | genus = Octopus | species = australis | authority = Hoyle, 1885 | synonyms = {{Species list | Robsonella australis | (Hoyle, 1885)}} | synonyms_ref = <ref name="worms">{{cite WoRMS |title=''Octopus australis'' |id=341948 |access-date=1 December 2022}}</ref> }}
'''''Octopus australis''''' (commonly the '''hammer octopus'''<ref name=":6">{{Cite web |last=Runck |first=Allison |date=2021-09-29 |title=Hammer Octopus |url=https://australian.museum/learn/animals/molluscs/hammer-octopus-octopus-australis/australian.museum/learn/animals/molluscs/hammer-octopus-octopus-australis/ |access-date=2022-12-01 |website=The Australian Museum |language=en}}</ref><ref name=":0">{{Cite web |last1=Hall |first1=Karina |last2=Roelofs |first2=Anthony |title=Hammer Octopus 2020 |url=https://fish.gov.au/report/412-Hammer-Octopus-2020 |access-date=2022-12-01 |website=Status of Australian Fish Stocks Reports |language=en}}</ref> or sometimes the '''southern octopus'''<ref name=":1">{{Cite book |url=https://www.dpi.nsw.gov.au/content/research/areas/fisheries-and-ecosystems/wild-fisheries/outputs/2010/1797/StatusOfFisheriesResourcesNSW2008-09.pdf |title=Status of Fisheries Resources in NSW 2008/09 |publisher=NSW Industry & Investment |year=2010 |editor-last=Rowling |editor-first=Kevin |location=Cronulla, Australia |language=en |editor-last2=Hegarty |editor-first2=Anne-Marie |editor-last3=Ives |editor-first3=Matthew}}</ref><ref name=":2">{{Cite book |last1=Wadley |first1=Victoria |title=Cephalopods of commercial importance in Australian fisheries |last2=Dunning |first2=Malcolm |publisher=Australian Fisheries Management Authority |year=1998 |location=Canberra, Australia |language=en |oclc=680485378}}</ref><ref name=":3">{{Cite web |last= |first= |title=Species: Octopus australis (Southern Octopus) |url=https://bie.ala.org.au/species/https://biodiversity.org.au/afd/taxa/087a6334-8cd5-4821-a8cb-7c50135096ab |access-date=2022-12-01 |website=Atlas of Living Australia |language=en-AU}}</ref>) is a species of octopus.<ref name="worms"/> It gets the common name hammer octopus from a modified arm possessed by males and used in reproduction.<ref name=":7">{{Cite book |last1=Norman |first1=Mark |title=A Guide to Squid, Cuttlefish and Octopuses of Australasia. |last2=Reid |first2=Amanda |date=2000-05-23 |publisher=CSIRO Publishing |isbn=0-643-06577-6 |location=Clayton, Australia |page=61 |language=en |oclc=1178534127}}</ref><ref name=":6" /> It was first described by William Evans Hoyle<ref>{{Cite web |title=Octopus australis Hoyle, 1885 |url=https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=556177#null |access-date=2022-12-01 |website=Integrated Taxonomic Information System}}</ref> in 1885,<ref name=":3" /> based on a specimen found in Port Jackson in New South Wales.<ref>{{Cite journal |last=Tait |first=R. W. |date=1982 |title=A taxonomic revision of Octopus australis Hoyle, 1885 (Octopodidae: Cephalopoda), with a redescription of the species |journal=Memoirs of Museum Victoria |volume=43 |issue=1 |pages=15–23 |doi=10.24199/j.mmv.1982.43.02 |issn=0083-5986|doi-access=free }}</ref>
== Description == ''O. australis'' is medium-sized,<ref name=":3" /> with a mature mantle length of around 20 to 25 millimeters for males and 50 to 60 millimeters for females,<ref name=":2" /> an arm span of around 40 centimeters,<ref name=":1" /> and a maximum total length of 49.9 centimeters.<ref name=":0" /> Males weigh around 210 grams and females around 105 grams.<ref name=":4">{{Cite journal |last1=Winstanley |first1=R. H. |last2=Potter |first2=M. A. |last3=Caton |first3=A. E. |date=1983-06-30 |title=Australian cephalopod resources |url=https://museumsvictoria.com.au/collections-research/journals/memoirs-of-museum-victoria/volume-44-1983/243-253/ |journal=Memoirs of Museum Victoria |language=English |volume=44 |pages=243–253 |doi=10.24199/j.mmv.1983.44.19|doi-access=free }}</ref> The head of ''O. australis'' is narrow and egg-shaped and it has small eyes.<ref name=":5">{{Cite journal |last1=Stranks |first1=T. N. |last2=Norman |first2=Mark D. |date=1992 |title=Review of the Octopus australis complex from Australia and New Zealand, with description of a new species (Mollusca: Cephalopoda) |journal=Memoirs of Museum Victoria |volume=53 |issue=2 |pages=345–373 |doi=10.24199/j.mmv.1992.53.15 |issn=0814-1827|doi-access=free }}</ref> It is typically a sandy cream color.<ref name=":7" /><ref name=":6" />
== Distribution == ''O. australis'' is found in coastal waters and bays<ref name=":2" /> along the eastern coast of Australia from central Queensland to southern New South Wales,<ref name=":0" /> most commonly in subtropical inshore waters, and from depths of around 3 to 140 meters.<ref name=":2" /> It tends to live on sand or mud seafloors,<ref name=":5" /> among sponges, ascidians, or mollusks, or in seagrass.<ref name=":4" />
== Diet == The diet of ''O. australis'' is mostly composed of isopods,<ref name=":8">{{Cite web |date=2007-09-01 |editor-last=Tzioumis |editor-first=Vicky |editor2-last=Keable |editor2-first=Stephen |title=Description of Key Species Groups in the East Marine Region |url=https://parksaustralia.gov.au/marine/pub/scientific-publications/archive/key-species.pdf |access-date=2022-12-05 |website=Australian Marine Parks |publisher=Australian Museum |language=en-au}}</ref> but they also eat other types of crustaceans, other octopuses, bristle worms, gastropods, and bivalves.<ref name=":5" /> They usually forage at night and hide in trash, shells, or the seafloor during the day.<ref>{{Cite book |url=https://www.fao.org/3/i3489e/i3489e.pdf |title=Cephalopods of the World: An Annotated and Illustrated Catalogue of Cephalopod Species Known to Date |publisher=Food and Agriculture Organization of the United Nations |year=2016 |isbn=978-92-5-107989-8 |editor-last=Jereb |editor-first=Patrizia |volume=3: Octopods and Vampire Squids |location=Rome |language=en |editor-last2=Roper |editor-first2=Clyde F. E. |editor-last3=Norman |editor-first3=Mark D. |editor-last4=Finn |editor-first4=Julian K.}}</ref>
== Life cycle == Females lay around 50 to 130 eggs per brood,<ref name=":8" /> each egg being about 11 millimeters long. They normally lay eggs in the summer. Eggs take over 100 days to hatch. ''O. australis'' have an estimated lifespan of 18 to 20 months.<ref name=":4" /><ref name=":8" />
== References == {{Reflist}}
{{Taxonbar|from=Q2699589}}
Category:Octopodidae Category:Cephalopods described in 1885 Category:Cephalopods of Australia
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