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{{short description|Family of aquatic flightless birds}}
{{Other uses}}
{{About|2=the bird known as a penguin originally|3=Great Auk}}
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{{Use mdy dates|date=November 2014}}
{{Automatic taxobox
| name = Penguins
| fossil_range = Late [[Danian]]-[[Holocene|Recent]], {{fossilrange|62|0|earliest=66}} <small>Possible [[Cretaceous]] origin according to molecular data<ref name=tambussi>{{cite journal|first1=C.|last1=Tambussi|first2=C. A.|last2=Hospitaleche|year=2007|url=http://www.scielo.org.ar/pdf/raga/v62n4/v62n4a12.pdf|title=Antarctic birds (Neornithes) during the Cretaceous–Eocene time|journal=Revista de la Asociación Geológica|volume=62|issue=4|pages=604–617|access-date=March 21, 2021|archive-date=April 2, 2021|archive-url=https://web.archive.org/web/20210402124554/http://www.scielo.org.ar/pdf/raga/v62n4/v62n4a12.pdf|url-status=live}}</ref><ref>{{cite journal|last1=Hackett|first1=S. J.|first2=R. T.|last2=Kimball|first3=S.|last3=Reddy|first4=R. C. K.|last4=Bowie|first5=E. L.|last5=Braun|first6=M. J.|last6=Braun|year=2008|title=A Phylogenomic Study of Birds Reveals Their Evolutionary History|journal=Science|volume=320|issue=5884|pages=1763–1768|doi=10.1126/science.1157704|pmid=18583609|bibcode=2008Sci...320.1763H|s2cid=6472805}}</ref><ref name="Ksepka"/></small>
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| perrow = 2/2
| total_width = 275
| caption_align = center
|image1= Aptenodytes forsteri -Snow Hill Island, Antarctica -adults and juvenile-8.jpg
|
|image2 = South Shetland-2016-Deception Island–Chinstrap penguin (Pygoscelis antarctica) 04.jpg
|caption2 = [[Chinstrap penguin|Chinstrap]]
|image3 = Snares Penguin (Eudyptes robustus) -group.jpg
|caption3 = [[Snares penguin|Snares]]
|image4 = African penguin side profile.jpg
|caption4 = [[African penguin|African]]
| border = infobox
}}
| display_parents = 2
| parent_authority = [[Richard Bowdler Sharpe|Sharpe]], 1891
| taxon = Spheniscidae
| authority = [[Charles Lucien Bonaparte|Bonaparte]], 1831
| range_map = Penguin range.png
| range_map_caption = Breeding range of penguins, all species (aqua); some species have wider seasonal migration ranges
| subdivision_ranks = Modern [[genus|genera]]
| subdivision =
*
*
*
*
*
*
}}
'''Penguins''' are a group of [[Water bird|aquatic]] [[flightless bird]]s from the [[family (biology)|family]] '''Spheniscidae''' ({{IPAc-en|s|f|ᵻ|ˈ|n|ɪ|s|ᵻ|d|iː|,_|-|d|aI}}) of the [[order (biology)|order]] '''Sphenisciformes''' ({{IPAc-en|s|f|ᵻ|ˈ|n|ɪ|s|@|f|ɔr|m|iː|z}}).<ref name="IOU">{{cite web |url=https://www.worldbirdnames.org/bow/loons/ |title=Kagu, Sunbittern, tropicbirds, loons, penguins |editor1-last=Gill |editor1-first=Frank |editor2-last=Donsker |editor2-first=David |editor3-last=Rasmussen |editor3-first=Pamela |year=2023 |work=World Bird List Version 13.1 |publisher=International Ornithologists' Union |access-date=April 16, 2023 |archive-date=April 27, 2020 |archive-url=https://web.archive.org/web/20200427191432/https://www.worldbirdnames.org/bow/loons/ |url-status=live }}</ref> They live almost exclusively in the [[Southern Hemisphere]]. Only one [[species]], the [[Galápagos penguin]], is equatorial, with a small portion of its population extending slightly north of the equator (within a quarter degree of latitude). Highly adapted for life in the ocean water, penguins have [[Countershading|countershaded]] dark and white [[plumage]] and flippers for swimming. Most penguins feed on [[krill]], [[fish]], [[squid]] and other forms of [[sea life]] which they catch with their bills and swallow whole while swimming. A penguin has a spiny tongue and powerful jaws to grip slippery prey.<ref>{{Cite web |title=Diet and Eating Habits |url=https://seaworld.org/animals/all-about/penguin/diet-and-eating-habits/ |website=Sea World Parks and Entertainment |access-date=July 19, 2024 |archive-date=July 10, 2024 |archive-url=https://web.archive.org/web/20240710195609/https://seaworld.org/animals/all-about/penguin/diet-and-eating-habits/ |url-status=live }}</ref>
They spend about half of their lives on land and the other half in the sea. The largest living species is the [[emperor penguin]] (''Aptenodytes forsteri''):<ref>{{Cite book|url=https://books.google.com/books?id=TQjLDAAAQBAJ&q=largest+living+species+of+penguin+is+the+emperor+penguin&pg=PA124|title=Animal!|last=DK|year=2016|publisher=Penguin|isbn=9781465459008|language=en|access-date=November 18, 2020|archive-date=June 2, 2021|archive-url=https://web.archive.org/web/20210602214442/https://books.google.com/books?id=TQjLDAAAQBAJ&q=largest+living+species+of+penguin+is+the+emperor+penguin&pg=PA124|url-status=live}}</ref> on average, adults are about {{convert|1.1|m|ftin|abbr=on}} tall and weigh {{convert|35|kg|lb|abbr=on}}. The smallest penguin species is the [[Little penguin|little blue penguin]] (''Eudyptula minor''), also known as the fairy penguin, which stands around {{convert|30|-|33|cm|in|abbr=on}} tall and weighs {{convert|1.2|-|1.3|kg|lb|abbr=on}}.<ref name="pengsent">{{cite web|url=http://mesh.biology.washington.edu/penguinProject/Little|title=Little Penguin – Penguin Project|last=Grabski|first=Valerie|year=2009|publisher=Penguin Sentinels/University of Washington|url-status=dead|archive-url=https://web.archive.org/web/20111216162812/http://mesh.biology.washington.edu/penguinProject/Little|archive-date=December 16, 2011|access-date=September 24, 2022}}</ref> Today, larger penguins generally inhabit colder regions, and smaller penguins inhabit regions with temperate or [[tropical climate]]s. Some [[prehistoric]] penguin species were enormous: as tall or heavy as an adult human.<ref>{{Cite web |author1=Harry Baker |date=2023-02-08 |title=Largest penguin ever discovered weighed a whopping 340 pounds, fossils reveal |url=https://www.livescience.com/largest-penguin-ever-discovered-weighed-a-whopping-340-pounds-fossils-reveal |access-date=2024-08-04 |website=livescience.com |language=en}}</ref> There was a great diversity of species in [[subantarctic]] regions, and [[Palaeeudyptes klekowskii|at least one giant species]] in a region around 2,000 km south of the [[equator]] 35 [[Mya (unit)|mya]], during the Late [[Eocene]], a climate decidedly warmer than today.<ref>{{Cite journal|last1=Caballero |first1=Rodrigo |last2=Huber |first2=Matthew |date=August 27, 2013 |title=State-dependent climate sensitivity in past warm climates and its implications for future climate projections |journal=Proceedings of the National Academy of Sciences |language=en |volume=110 |issue=35 |pages=14162–14167 |doi=10.1073/pnas.1303365110 |issn=0027-8424 |pmc=3761583 |pmid=23918397|bibcode=2013PNAS..11014162C |doi-access=free}}</ref><!-- the distance is accurate for 35 million years ago; it is closer to the Equator today -->
==Etymology==
[[File:Great Auk (Pinguinis impennis) specimen, Kelvingrove, Glasgow - geograph.org.uk - 1108249.jpg|thumb|225x225px|The name penguin was first used in the late 16th century for the Great Auk (pictured here) and was later applied to Southern Hemisphere birds due to their resemblance, though they are not closely related.<ref name="Gaskell">{{cite book|url=https://books.google.com/books?id=tsUzeXV_7jcC&q=egg+%22Great+Auk%22&pg=PA152|title = Who Killed the Great Auk?|first = Jeremy|last = Gaskell|publisher = Oxford University Press (USA)|isbn = 0-19-856478-3|year = 2000|page = 152|access-date = November 18, 2020|archive-date = October 18, 2021|archive-url=https://web.archive.org/web/20211018043926/https://books.google.com/books?id=tsUzeXV_7jcC&q=egg+%22Great+Auk%22&pg=PA152|url-status = live}}</ref>|left]]
The word ''penguin'' first appears in literature at the end of the 16th century as a synonym for the [[great auk]].<ref name="Fuller">{{cite book |last1=Fuller |first1=Errol |author1-link=Errol Fuller |title=The Great Auk: The Extinction of the Original Penguin |date=2003 |publisher=Bunker Hill Publishing, Inc. |isbn=978-1-59373-003-1 |page=17 |url=https://books.google.com/books?id=35rGM50pAoAC |language=en}}</ref> When European explorers discovered what are today known as penguins in the Southern Hemisphere, they noticed their [[Convergent evolution|similar appearance]] to the great auk of the [[Northern Hemisphere]] and named them after this bird, although they are not closely related.<ref name="Crofford10"/>
The etymology of the word ''penguin'' is still debated. The English word is not apparently of [[French language|French]],<ref name="CNRTL">{{cite web |url=http://www.cnrtl.fr/etymologie/pingouin |title=PINGOUIN : Etymologie de PINGOUIN |publisher=Centre National de Ressources Textuelles et Lexicales |access-date=January 25, 2010 |archive-url=https://web.archive.org/web/20081026163135/http://www.cnrtl.fr/etymologie/Pingouin |archive-date=October 26, 2008 |url-status=live}}</ref> [[Breton language|Breton]]<ref name="Online Etymology Dictionary">{{OEtymD|penguin}}</ref> or [[Spanish language|Spanish]]<ref name="DRAE">
{{cite encyclopedia |encyclopedia=Diccionario de la lengua española |title=Pingüino |url=http://buscon.rae.es/draeI/SrvltConsulta?TIPO_BUS=3&LEMA=ping%C3%BCino |language=es-ES |edition=22nd |publisher=Real Academia Española |archive-url=https://web.archive.org/web/20110609035102/http://buscon.rae.es/draeI/SrvltConsulta?TIPO_BUS=3&LEMA=ping%C3%BCino |archive-date=June 9, 2011 |url-status=dead |quote=Del fr. pingouin}}</ref> origin (the latter two are attributed to the French word {{lang|fr|pingouin}}), but first appears in English or Dutch.<ref name="CNRTL" />
Some dictionaries suggest a derivation from [[Welsh language|Welsh]] {{lang|cy|pen}}, 'head' and {{lang|cy|gwyn}}, 'white',<ref>{{cite web |url=http://www.etymonline.com/index.php?term=penguin |title=penguin |website=Online Etymology Dictionary |access-date=April 29, 2016 |archive-url=https://web.archive.org/web/20160604130140/http://www.etymonline.com/index.php?term=penguin |archive-date=June 4, 2016 |url-status=live}}</ref> including the ''[[Oxford English Dictionary]]'', the ''[[American Heritage Dictionary]]'',<ref name="AHD">{{cite web |url=http://www.wordnik.com/words/penguin/etymology |title=penguin |work=Wordnik |access-date=October 7, 2014 |url-status=dead |archive-url=https://web.archive.org/web/20110905215701/http://www.wordnik.com/words/penguin |archive-date=September 5, 2011 }}</ref> the ''[[Century Dictionary]]''<ref name="AHD"/> and ''[[Merriam-Webster]]'',<ref name="MW">{{cite dictionary |url=http://www.merriam-webster.com/dictionary/penguin |title=Penguin – Definition |dictionary=[[Merriam-Webster]] |date=August 31, 2012 |access-date=September 8, 2013 |archive-url=https://web.archive.org/web/20131029185420/http://www.merriam-webster.com/dictionary/penguin |archive-date=October 29, 2013 |url-status=live}}</ref> on the basis that the name was originally applied to the great auk, either because it was found on [[White Head Island]] ({{langx|cy|Pen Gwyn}}) in Newfoundland, or because it had white circles around its eyes (though the head was black). However, the Welsh word {{lang|cy|pen}} can also be used to mean 'front' and, in a maritime context, {{lang|cy|pen blaen}} means 'front end or part, bow (of a ship), prow'.<ref>[https://welsh-dictionary.ac.uk/gpc/gpc.html Geiriadur Prifysgol Cymru]. Retrieved November 22, 2024.</ref>
An alternative etymology links the word to [[Latin language|Latin]] {{lang|la|pinguis}}, which means 'fat' or 'oil'.<ref>{{cite book |author1=Tui De Roy |author2=Mark Jones |author3=Julie Cornthwaite |title=Penguins:The Ultimate Guide |publisher=Princeton University Press |year=2013 |page=151 }}</ref> Support for this etymology can be found in the alternative Germanic word for penguin, {{lang|de|fettgans}} or 'fat-goose', and the related Dutch word {{lang|nl|vetgans}}.
Adult male penguins are sometimes called ''cocks'', females sometimes called ''hens''; a group of penguins on land is a ''waddle'', and a group of penguins in the water is a ''raft''.
=== Pinguinus ===
{{Main|Great auk}}
Since 1871, the Latin word ''Pinguinus'' has been used in [[Taxonomy (biology)|scientific classification]] to name the genus of the [[great auk]] (''Pinguinus impennis'', meaning "plump or fat without [[flight feather]]s"),<ref name="Gaskell">{{cite book|url=https://books.google.com/books?id=tsUzeXV_7jcC&q=egg+%22Great+Auk%22&pg=PA152|title = Who Killed the Great Auk?|first = Jeremy|last = Gaskell|publisher = Oxford University Press (USA)|isbn = 0-19-856478-3|year = 2000|page = 152|access-date = November 18, 2020|archive-date = October 18, 2021|archive-url=https://web.archive.org/web/20211018043926/https://books.google.com/books?id=tsUzeXV_7jcC&q=egg+%22Great+Auk%22&pg=PA152|url-status = live}}</ref> which became [[bird extinction|extinct]] in the mid-19th century.<ref name="Fuller"/> As confirmed by a 2004 genetic study, the genus ''Pinguinus'' belongs in the family of the [[auk]]s (Alcidae), within the order of the [[Charadriiformes]].<ref>{{Cite journal | doi = 10.1186/1471-2148-4-28| year = 2004| title = A supertree approach to shorebird phylogeny| last1 = Thomas | first1 = G. H. | journal = BMC Evolutionary Biology| volume = 4| pages = 28| last2 = Wills | first2 = M. A. | last3 = Székely | first3 = T. S. | pmid=15329156 | pmc=515296| doi-access = free}}</ref><ref name="Johnsgard">{{cite book |last=Johnsgard |first=Paul A. |author-link=Paul Johnsgard |title=Diving Birds of North America |publisher=University of Nebraska Press |___location=Lincoln |year=1987 |pages=[https://archive.org/details/divingbirdsofnor0000john/page/265 265–266] |isbn=0-8032-2566-0 |url=https://archive.org/details/divingbirdsofnor0000john/page/265 |access-date=May 11, 2010 |url-access=registration }}</ref>
The birds currently known as penguins were discovered later and were so named by sailors because of their physical resemblance to the great auk. Despite this resemblance, however, they are not auks, and are not closely related to the great auk.<ref name="Crofford10"/><ref name="Gaskell" /> They do not belong in the genus ''Pinguinus'', and are not classified in the same family and order as the great auk. They were classified in 1831 by [[Charles Lucien Bonaparte]] in several distinct genera within the family [[Spheniscidae]] and order [[Sphenisciformes]].
==Systematics and evolution==
=== Taxonomy ===
{{Main article|List of penguins}}
The family name of Spheniscidae was given by [[Charles Lucien Bonaparte]] from the genus [[Spheniscus]],<ref>{{cite book |last1=Fraser |first1=Ian |last2=Gray |first2=Jeannie |date=2019 |title=Australian Bird Names: Origins and Meanings |url=https://books.google.com/books?id=aTytDwAAQBAJ&dq=Sphenisciformes&pg=PA86 |___location=[[Clayton South, Victoria]], Australia |publisher=CSIRO Publishing |pages=86–87 |isbn=9781486311637 }}</ref> the name of that genus comes from the [[Greek language|Greek]] word {{lang|el|σφήν}} ''sphēn'' "[[wedge]]" used for the shape of an [[African penguin]]'s swimming flippers.<ref>{{cite book |last=Jobling |first=James A. |date=2010 |title=The Helm Dictionary of Scientific Bird Names |___location=London, England, UK |publisher=Helm Publishing |page=361 |isbn= 978-1-4081-2501-4 }}</ref>
Some recent sources<ref name="Ksepka"/><ref name="Clarke"/> apply the [[Phylogenetic taxonomy|phylogenetic taxon]] Spheniscidae to what here is referred to as Spheniscinae. Furthermore, they restrict the phylogenetic taxon Sphenisciformes to flightless taxa, and establish the phylogenetic taxon Pansphenisciformes as equivalent to the [[Linnean taxonomy|Linnean taxon]] Sphenisciformes,<ref name="Clarke"/> i.e., including any flying basal "proto-penguins" to be discovered eventually. Given that neither the relationships of the penguin subfamilies to each other nor the placement of the penguins in the avian [[phylogeny]] is presently resolved, this is confusing, so the established Linnean system is followed here.
The number of penguin species is typically listed as between seventeen and nineteen.<ref>{{Cite web |last=Hall |first=Danielle |date=April 2018 |editor-last=Fraser |editor-first=Bill |title=Penguins |url=https://ocean.si.edu/ocean-life/seabirds/penguins |access-date=October 27, 2024 |website=[[Smithsonian Institution]]}}</ref> The [[International Ornithologists' Union]] recognizes six genera and eighteen species:<ref>{{Cite web |date=August 21, 2024 |title=Kagu, Sunbittern, tropicbirds, loons, penguins |url=https://www.worldbirdnames.org/bow/loons/ |access-date=October 27, 2024 |website=[[IOC World Bird List]]}}</ref>
{| class="wikitable"
|+ Penguin genera
! Genus !! Species !! Image of [[type species]]
|-
| ''[[Eudyptes]]'' || {{bulleted list|[[Macaroni penguin]] (''E. chrysolophus'')|[[Royal penguin]] (''E. schlegeli'')|[[Northern rockhopper penguin]] (''E. moseleyi'')|[[Southern rockhopper penguin]] (''E. chrysocome'')|[[Fiordland penguin]] (''E. pachyrhynchus'')|[[Snares penguin]] (''E. robustus'')|[[Erect-crested penguin]] (''E. sclateri'')}} || [[File:Falkland Islands Penguins 70.jpg|200px]]<br>Southern rockhopper penguin
|-
| ''[[Spheniscus]]'' || {{bulleted list|[[Galapagos penguin]] (''S. mendiculus'')|[[Humboldt penguin]] (''S. humboldti'')|[[Magellanic penguin]] (''S. magellanicus'')|[[African penguin]] (''S. demersus'')}} || [[File:Pingüino de El Cabo (Spheniscus demersus), Playa de Boulders, Simon's Town, Sudáfrica, 2018-07-23, DD 10.jpg|200px]]<br>African penguin
|-
| ''[[Pygoscelis]]'' || {{bulleted list|[[Adélie penguin]] (''P. adeliae'')|[[Chinstrap penguin]] (''P. antarcticus'')|[[Gentoo penguin]] (''P. papua'')}} || [[File:Pygoscelis antarcticus head.jpg|200px]]<br>Chinstrap penguin
|-
| ''[[Aptenodytes]]'' || {{bulleted list|[[King penguin]] (''A. patagonicus'')|[[Emperor penguin]] (''A.forsteri'')}} || [[File:Falkland Islands Penguins 49.jpg|200px]]<br>King penguin
|-
| ''[[Eudyptula]]'' || {{bulleted list|[[Little penguin]] (''E. minor'')}} || [[File:(1)Little Penguin-4.jpg|200px]]<br>Little penguin
|-
| ''[[Megadyptes]]'' || {{bulleted list|[[Yellow-eyed penguin]] (''M. antipodes'')}} || [[File:Yellow-eyed Penguin 3.jpg|200px]]<br>Yellow-eyed penguin
|}
===Evolution===
[[File:CSIRO ScienceImage 11266 Penguin tracks.jpg|thumb|Penguin tracks in the sand on [[Bruny Island]], [[Tasmania]]]]
Although the [[evolution]]ary and [[biogeography|biogeographic]] history of Sphenisciformes is well-researched, many prehistoric forms are not [[Taxonomy#Alpha and beta taxonomy|fully described]]. <!-- Although penguin bones of any one species vary in size and few good specimens are known. Commenting this out as I have no idea how to properly integrate it into the text --> Some seminal articles about the evolutionary history of penguins have been published since 2005.<ref name="Ksepka"/><ref name="Baker"/><ref name="B&G">{{Cite journal | doi = 10.1111/j.1096-0031.2005.00065.x| title = A phylogeny of extant penguins (Aves: Sphenisciformes) combining morphology and mitochondrial sequences| journal = Cladistics| volume = 21| issue = 3| pages = 209–239| year = 2005| last1 = Bertelli | first1 = S. | last2 = Giannini | first2 = N. P. | s2cid = 85071808}}</ref><ref name="Slack">{{cite journal| doi = 10.1093/molbev/msj124| last1 = Slack| first1 = Kerryn E.| last2 = Jones| first2 = Craig M.| last3 = Ando| first3 = Tatsuro| last4 = Harrison| first4 = G.L. "Abby"| last5 = Fordyce| first5 = R. Ewan| last6 = Arnason| first6 = Ulfur| last7 = Penny| first7 = David| year = 2006| title = Early Penguin Fossils, plus Mitochondrial Genomes, Calibrate Avian Evolution| journal = [[Molecular Biology and Evolution]]| volume = 23| issue = #6| pages = 1144–1155| pmid = 16533822| citeseerx = 10.1.1.113.4549}} [http://mbe.oxfordjournals.org/cgi/content/full/msj124/DC1 Supplementary Material] {{Webarchive|url=https://web.archive.org/web/20091216110914/http://mbe.oxfordjournals.org/cgi/content/full/msj124/DC1 |date=December 16, 2009 }}</ref>{{overcite|date=October 2024}}<!-- This entire paragraph should probably be rewritten and updated -->
The [[Basal (phylogenetics)|basal]] penguins lived around the time of the [[Cretaceous–Paleogene extinction event]] in the general area of southern New Zealand and [[Byrd Land]], Antarctica.<ref name="Ksepka"/> Due to [[plate tectonics]], these areas were at that time less than {{convert|1500|km|mi}} apart rather than {{convert|4000|km|mi}}. The [[most recent common ancestor]] of penguins and [[Procellariiformes]] can be roughly dated to the [[Campanian]]–[[Maastrichtian]] boundary, around 70–68 mya.<ref name="Baker"/><ref name="Slack"/><ref>The exact divergence dates according to [[#Baker|Baker]] ''et al.'' (2006) mentioned in this section are not as precisely resolved, due to uncertainties of the [[molecular clock]] used.</ref>
====Basal fossils====
The oldest known [[fossil]] penguin species are known from the [[Waipara Greensand]] of New Zealand, which spans the late [[Danian]] to early [[Thanetian]] stages (~62.5–58 Ma) of the [[Paleocene]] epoch. Several genera have been named from these outcrops, including ''[[Archaeodyptes]]'', ''[[Daniadyptes]]'', ''[[Muriwaimanu]]'', ''[[Sequiwaimanu]]'', ''[[Waimanu]]'', ''[[Waimanutaha]]'', and ''[[Waiparadyptes]]''.<ref name="WaiparaPenguins">{{Cite journal |last1=Mayr |first1=Gerald |author1-link=Gerald Mayr |last2=De Pietri |first2=Vanesa L. |last3=Proffitt |first3=James |last4=Blokland |first4=Jacob C. |last5=Clarke |first5=Julia A. |author5-link=Julia Clarke |last6=Love |first6=Leigh |last7=Mannering |first7=Al A. |last8=Crouch |first8=Erica M. |last9=Reid |first9=Catherine |last10=Scofield |first10=R. Paul |date=2025-08-12 |title=Multiple exceptionally preserved fossils from the Paleocene Waipara Greensand inform the diversity of the oldest stem group Sphenisciformes and the formation of their diving adaptations |url=https://academic.oup.com/zoolinnean/article-abstract/204/4/zlaf080/8230366 |journal=Zoological Journal of the Linnean Society |language=en |volume=204 |issue=4 |pages=zlaf080 |doi=10.1093/zoolinnean/zlaf080 |issn=0024-4082}}</ref> While they were not as well-adapted to aquatic life as modern penguins, they were still flightless, with short wings adapted for deep diving.<ref name="Slack"/> They swam on the surface using mainly their feet, but the wings were—as opposed to most other diving birds (both living and extinct)—already adapting to underwater locomotion.<ref>{{Cite journal | doi = 10.1073/pnas.1304838110| title = High flight costs, but low dive costs, in auks support the biomechanical hypothesis for flightlessness in penguins| journal = Proceedings of the National Academy of Sciences| volume = 110| issue = #23| pages = 9380–9384| year = 2013| last1 = Elliott | first1 = K. H.| last2 = Ricklefs | first2 = R. E.| last3 = Gaston | first3 = A. J.| last4 = Hatch | first4 = S. A.| last5 = Speakman | first5 = J. R.| last6 = Davoren | first6 = G. K. | pmid=23690614 | pmc=3677478| bibcode = 2013PNAS..110.9380E| doi-access = free}}</ref>
''[[Perudyptes]]'' from northern Peru was dated to 42 mya. An unnamed fossil from [[Argentina]] proves that, by the [[Bartonian]] (Middle Eocene), some 39–38 mya,<ref>''Contra'' [[#Baker|Baker]] ''et al.'' (2006).</ref> primitive penguins had spread to [[South America]] and were in the process of expanding into [[Atlantic]] waters.<ref name="Clarke"/><!-- This entire paragraph needs to be rewritten, but I'm not sure how to -->
====Palaeeudyptines====
During the Late Eocene and the Early [[Oligocene]] (40–30 mya), some lineages of gigantic penguins existed. [[Nordenskjoeld's giant penguin]] was the tallest, growing nearly {{convert|1.80|m|ft|abbr=off|sp=us}} tall. The [[New Zealand giant penguin]] was probably the heaviest, weighing {{Convert|80|kg|lb}} or more. Both were found on New Zealand, the former also in the Antarctic farther eastwards.
Traditionally, most extinct species of penguins, giant or small, had been placed in the [[paraphyletic]] [[subfamily]] called [[Palaeeudyptinae]]. More recently, with new taxa being discovered and placed in the [[phylogeny]] if possible, it is becoming accepted that there were at least two major extinct lineages. One or two closely related ones occurred in [[Patagonia]], and at least one other—which is or includes the paleeudyptines as recognized today – occurred on most [[Antarctic]] and [[Subantarctic]] coasts.
Size plasticity was significant at this initial stage of [[Adaptive radiation|radiation]]: on [[Seymour Island]], Antarctica, for example, around 10 known species of penguins ranging in size from medium to large apparently coexisted some 35 mya during the [[Priabonian]] (Late Eocene).<ref name="Jadwiszczak"/> It is not known whether the palaeeudyptines constitute a [[monophyletic]] lineage, or whether gigantism was evolved independently in a restricted Palaeeudyptinae and the Anthropornithinae – whether they were considered valid, or whether there was a wide size range present in the Palaeeudyptinae as delimited (i.e., including ''[[Anthropornis nordenskjoeldi]]'').<ref name="Ksepka"/> The oldest well-described giant penguin, the {{convert|5|ft|m|adj=on}}-tall ''[[Icadyptes salasi]]'', existed as far north as northern [[Peru]] about 36 mya.
Gigantic penguins had disappeared by the end of the [[Paleogene]], around 25 mya. Their decline and disappearance coincided with the spread of the [[Squalodontidae]] and other primitive, fish-eating [[toothed whale]]s, which competed with them for food and were ultimately more successful.<ref name="Baker"/> A new lineage, the [[Paraptenodytes]], which includes smaller and stout-legged forms, had already arisen in southernmost South America by that time. The early [[Neogene]] saw the emergence of another morphotype in the same area, the similarly sized but more gracile [[Palaeospheniscinae]], as well as the radiation that gave rise to the current [[biodiversity]] of penguins.
====Origin and systematics of modern penguins====
Modern penguins constitute two undisputed [[clade]]s and another two more basal genera with more ambiguous relationships.<ref name="B&G"/> To help resolve the evolution of this [[Order (biology)|order]], 19 high-coverage genomes that, together with two previously published genomes, encompass all extant penguin species have been sequenced.<ref>{{Cite journal |last1=Pan |first1=Hailin |last2=Cole |first2=Theresa L. |last3=Bi |first3=Xupeng |last4=Fang |first4=Miaoquan |last5=Zhou |first5=Chengran |last6=Yang |first6=Zhengtao |last7=Ksepka |first7=Daniel T. |last8=Hart |first8=Tom |last9=Bouzat |first9=Juan L. |last10=Argilla |first10=Lisa S. |author-link10=Lisa Argilla |last11=Bertelsen |first11=Mads F. |date=September 1, 2019 |title=High-coverage genomes to elucidate the evolution of penguins |url= |journal=GigaScience |language=en |volume=8 |issue=9 |doi=10.1093/gigascience/giz117 |pmc=6904868 |pmid=31531675}}</ref> The origin of the Spheniscinae lies probably in the latest Paleogene and, geographically, it must have been much the same as the general area in which the order evolved: the oceans between the Australia-New Zealand region and the Antarctic.<ref name="Baker"/> Presumably diverging from other penguins around 40 mya,<ref name="Baker"/> it seems that the Spheniscinae were for quite some time limited to their ancestral area, as the well-researched deposits of the [[Antarctic Peninsula]] and [[Patagonia]] have not yielded Paleogene fossils of the subfamily. Also, the earliest spheniscine lineages are those with the most southern distribution.
The genus ''[[Aptenodytes]]'' appears to be the basalmost divergence among living penguins.<ref name="Ksepka">{{cite journal |doi=10.1111/j.1096-0031.2006.00116.x |last1=Ksepka |first1=D. T. |last2=Bertelli |first2=S. |last3=Giannini |first3=N. P. |title=The phylogeny of the living and fossil Sphenisciformes (penguins) |journal=Cladistics |volume=22 |year=2006 |pages=412–441 |issue=#5 |s2cid=85673628 |doi-access=free }}</ref><ref name=CB08>{{cite book |title=Systematics and Taxonomy of Australian Birds|vauthors=Christidis L, Boles WE |year=2008 |publisher=CSIRO Publishing |___location=Canberra |isbn=978-0-643-06511-6 |page=97}}</ref> They have bright yellow-orange neck, breast, and bill patches; incubate by placing their eggs on their feet, and when they hatch the chicks are almost naked. This genus has a distribution centred on the Antarctic coasts and barely extends to some Subantarctic islands today.
''[[Pygoscelis]]'' contains species with a fairly simple black-and-white head pattern; their distribution is intermediate, centred on Antarctic coasts but extending somewhat northwards from there. In external [[morphology (biology)|morphology]], these apparently still resemble the common ancestor of the Spheniscinae, as ''Aptenodytes''{{'}} [[autapomorph]]ies are, in most cases, fairly pronounced [[Adaptation (biology)|adaptations]] related to that genus' extreme [[habitat]] conditions. As the former genus, ''Pygoscelis'' seems to have diverged during the Bartonian,<ref>
It is likely that, during the Bartonian, there was a near-synchronous but [[allopatric]] split between the ancestors of ''Aptenodytes'', ''Pygoscelis'', and the common ancestor of all remaining genera ([[#Baker|Baker]]).</ref> but the range expansion and radiation that led to the present-day diversity probably did not occur until much later; around the [[Burdigalian]] stage of the Early [[Miocene]], roughly 20–15 mya.<ref name="Baker"/>
The [[Genus|genera]] ''[[Spheniscus]]'' and ''[[Eudyptula]]'' contain species with a mostly Subantarctic distribution centred on [[South America]]; some, however, range quite far northwards. They all lack [[carotenoid]] colouration and the former genus has a conspicuous banded head pattern; they are unique among living penguins by nesting in burrows. This group probably radiated eastwards with the [[Antarctic Circumpolar Current]] out of the ancestral range of modern penguins throughout the [[Chattian]] (Late Oligocene), starting approximately 28 mya.<ref name="Baker"/> While the two genera separated during this time, the present-day diversity is the result of a [[Pliocene]] radiation, taking place some 4–2 mya.<ref name="Baker"/>
The ''Megadyptes''–''Eudyptes'' clade occurs at similar [[latitude]]s (though not as far north as the [[Galápagos penguin]]), has its highest diversity in the New Zealand region, and represents a westward dispersal. They are characterized by hairy yellow ornamental head feathers; their bills are at least partly red. These two genera diverged apparently in the Middle Miocene ([[Langhian]], roughly 15–14 mya), although the living species of ''Eudyptes'' are the product of a later radiation, stretching from about the late [[Tortonian]] (Late Miocene, 8 mya) to the end of the Pliocene.<ref name="Baker"/>
===
The geographical and temporal pattern of spheniscine evolution corresponds closely to two episodes of [[global cooling]] documented in the [[Paleoclimatology|paleoclimatic record]].<ref name="Baker" /> The emergence of the Subantarctic lineage at the end of the Bartonian corresponds with the onset of the slow period of cooling that eventually led to the [[Quaternary glaciation|ice ages]] some 35 million years later. With habitat on the Antarctic coasts declining, by the Priabonian more hospitable conditions for most penguins existed in the Subantarctic regions rather than in Antarctica itself.<ref name="Baker, A., Pereira, SL, Haddrath, OP, Edge, KA 2006">{{cite journal |author=Baker, A., Pereira, SL, Haddrath, OP, Edge, KA |title=Multiple gene evidence for expansion of extant penguins out of Antarctica due to global cooling |journal=Proceedings of the Royal Society B: Biological Sciences |volume=273 |year=2006 |doi=10.1098/rspb.2005.3260 |issue=#1582 |pages=11–7 |pmid=16519228 |pmc=1560011}}</ref> Notably, the cold Antarctic Circumpolar Current also started as a continuous circumpolar flow only around 30 mya, on the one hand forcing the Antarctic cooling, and on the other facilitating the eastward expansion of ''[[Spheniscus]]'' to South America and eventually beyond.<ref name="Baker" /> Despite this, there is no fossil evidence to support the idea of crown radiation from the Antarctic continent in the Paleogene, although DNA study favors such a radiation.<ref name="Baker, A., Pereira, SL, Haddrath, OP, Edge, KA 2006"/>
Later, an interspersed period of slight warming was ended by the [[Middle Miocene Climate Transition]], a sharp drop in global average temperature from 14 to 12 mya, and similar abrupt cooling events followed at 8 mya and 4 mya; by the end of the Tortonian, the [[Antarctic ice sheet]] was already much like today in volume and extent. The emergence of most of today's Subantarctic penguin species almost certainly was caused by this sequence of Neogene climate shifts.
====Relationship to other bird orders====
Penguin ancestry beyond ''[[Waimanu]]'' remains unknown and not well-resolved by molecular or morphological analyses. The latter tend to be confounded by the strong adaptive [[Autapomorphy|autapomorphies]] of the Sphenisciformes; a sometimes perceived fairly close relationship between penguins and [[grebe]]s is almost certainly an error based on both groups' strong diving adaptations, which are [[homoplasies]]. On the other hand, different [[DNA sequence]] datasets do not agree in detail with each other either.
[[File:Spheniscus humboldti -swimming -aquarium-8a.jpg|thumb|Humboldt penguins in an aquarium. The penguin is an accomplished swimmer, having [[Flipper (anatomy)|flippers]] instead of wings.]]
What seems clear is that penguins belong to a clade of [[Neoaves]] (living birds except for [[paleognath]]s and [[fowl]]) that comprises what is sometimes called "[[Aequornithes|higher waterbirds]]" to distinguish them from the more ancient [[waterfowl]]. This group contains such birds as [[stork]]s, [[Rallidae|rails]], and the [[seabird]]s, with the possible exception of the [[Charadriiformes]].<ref>{{Cite journal|doi=10.1554/04-235 |url=http://biology-web.nmsu.edu/houde/Parallel_radiations.pdf |pmid=15612298 |title=Parallel Radiations in the Primary Clades of Birds |journal=Evolution |volume=58 |issue=11 |pages=2558–73 |year=2004 |last1=Fain |first1=M. G. |last2=Houde |first2=P. |bibcode=2004Evolu..58.2558F |s2cid=1296408 |url-status=dead |archive-url=https://web.archive.org/web/20130407204436/http://biology-web.nmsu.edu/houde/Parallel_radiations.pdf |archive-date=April 7, 2013 }}</ref>
Inside this group, penguin relationships are far less clear. Depending on the analysis and dataset, a close relationship to [[Ciconiiformes]]<ref name="Slack"/> or to [[Procellariiformes]]<ref name="Baker"/> has been suggested. Some think the penguin-like [[Plotopteridae|plotopterids]] (usually considered relatives of [[cormorant]]s and [[anhinga]]s) may actually be a sister group of the penguins and those penguins may have ultimately shared a common ancestor with the [[Pelecaniformes]] and consequently would have to be included in that order, or that the plotopterids were not as close to other pelecaniforms as generally assumed, which would necessitate splitting the traditional Pelecaniformes into three.<ref>{{Cite journal| doi = 10.1111/j.1439-0469.2004.00291.x|url=http://www.senckenberg.de/files/content/forschung/abteilung/terrzool/ornithologie/plotopteridae.pdf| title = Tertiary plotopterids (Aves, Plotopteridae) and a novel hypothesis on the phylogenetic relationships of penguins (Spheniscidae)| journal = Journal of Zoological Systematics and Evolutionary Research| volume = 43| pages = 61–71| year = 2005| last1 = Mayr| first1 = G.| access-date = July 8, 2006| archive-url=https://web.archive.org/web/20061013085236/http://www.senckenberg.de/files/content/forschung/abteilung/terrzool/ornithologie/plotopteridae.pdf| archive-date = October 13, 2006| url-status = live}}</ref>
A 2014 analysis of whole genomes of 48 representative bird species has concluded that penguins are the [[sister group]] of Procellariiformes,<ref name = "Jarvis2014">{{Cite journal| doi = 10.1126/science.1253451| pmid = 25504713|url=https://pgl.soe.ucsc.edu/jarvis14.pdf| title = Whole-genome analyses resolve early branches in the tree of life of modern birds| journal = Science| volume = 346| issue = #6215| pages = 1320–1331| date = 2014| last1 = Jarvis| first1 = E. D.| author1-link = Erich Jarvis| last2 = Mirarab| first2 = S.| last3 = Aberer| first3 = A. J.| last4 = Li| first4 = B.| last5 = Houde| first5 = P.| last6 = Li| first6 = C.| last7 = Ho| first7 = S. Y. W.| last8 = Faircloth| first8 = B. C.| last9 = Nabholz| first9 = B.| last10 = Howard| first10 = J. T.| last11 = Suh| first11 = A.| last12 = Weber| first12 = C. C.| last13 = Da Fonseca| first13 = R. R.| last14 = Li| first14 = J.| last15 = Zhang| first15 = F.| last16 = Li| first16 = H.| last17 = Zhou| first17 = L.| last18 = Narula| first18 = N.| last19 = Liu| first19 = L.| last20 = Ganapathy| first20 = G.| last21 = Boussau| first21 = B.| last22 = Bayzid| first22 = M. S.| last23 = Zavidovych| first23 = V.| last24 = Subramanian| first24 = S.| last25 = Gabaldon| first25 = T.| last26 = Capella-Gutierrez| first26 = S.| last27 = Huerta-Cepas| first27 = J.| last28 = Rekepalli| first28 = B.| last29 = Munch| first29 = K.| last30 = Schierup| first30 = M.| display-authors = 29| pmc = 4405904| bibcode = 2014Sci...346.1320J| hdl = 10072/67425| access-date = August 28, 2015| archive-url=https://web.archive.org/web/20150224020622/http://pgl.soe.ucsc.edu/jarvis14.pdf| archive-date = February 24, 2015| url-status = dead}}</ref> from which they diverged about 60 million years ago (95% CI, 56.8–62.7).<ref name = "LiC2014">{{Cite journal | doi = 10.1186/2047-217X-3-27| title = Two Antarctic penguin genomes reveal insights into their evolutionary history and molecular changes related to the Antarctic environment| journal = GigaScience| volume = 3| issue = #1| pages = 27| date = December 12, 2014| last1 = Li | first1 = C. | last2 = Zhang | first2 = Y. | last3 = Li | first3 = J. | last4 = Kong | first4 = L. | last5 = Hu | first5 = H. | last6 = Pan | first6 = H. | last7 = Xu | first7 = L. | last8 = Deng | first8 = Y. | last9 = Li | first9 = Q. | last10 = Jin | first10 = L. | last11 = Yu | first11 = H. | last12 = Chen | first12 = Y. | last13 = Liu | first13 = B. | last14 = Yang | first14 = L. | last15 = Liu | first15 = S. | last16 = Zhang | first16 = Y. | last17 = Lang | first17 = Y. | last18 = Xia | first18 = J. | last19 = He | first19 = W. | last20 = Shi | first20 = Q. | last21 = Subramanian | first21 = S. | last22 = Millar | first22 = C. D. | last23 = Meader | first23 = S. | last24 = Rands | first24 = C. M. | last25 = Fujita | first25 = M. K. | last26 = Greenwold | first26 = M. J. | last27 = Castoe | first27 = T. A. | last28 = Pollock | first28 = D. D. | last29 = Gu | first29 = W. | last30 = Nam | first30 = K. | display-authors = 29 | pmid=25671092 | pmc=4322438| doi-access = free}}</ref>
The distantly related [[puffin]]s, which live in the North Pacific and North Atlantic, developed similar characteristics to survive in the Arctic and sub-Arctic environments. Like the penguins, puffins have a white chest, black back and short stubby wings providing excellent swimming ability in icy water. But, unlike penguins, puffins can fly, as flightless birds would not survive alongside land-based predators such as polar bears and foxes; there are no such predators in the Antarctic. Their similarities indicate that similar environments, although at great distances, can result in similar evolutionary developments, i.e. [[convergent evolution]].<ref>{{Cite book |title=Introduction to Marine Biology |last=Karleskint |first=George |publisher=Cengage Publishing |year=2012 |isbn=978-1285402222 |pages=30 |url=https://books.google.com/books?id=9fEKAAAAQBAJ |access-date=August 15, 2018 |archive-date=July 21, 2020 |archive-url=https://web.archive.org/web/20200721052701/https://books.google.com/books?id=9fEKAAAAQBAJ |url-status=live }}</ref>
==Anatomy and physiology==
[[File:Penguin Wing.svg|thumb|Penguin wings have the same general bone structure as flighted birds, but the bones are shorter and stouter to allow them to serve as fins. 1). Humerus 2). Sesamoid Bone 3). Radius 4). Ulna 5). Radial Carpal bone 6). Carpometacarpus 7). Phalanges]]
[[File:Taxidermy of a penguin skin.jpg|thumb|Taxidermized penguin skin]]
Penguins are superbly adapted to [[Aquatic ecosystem|aquatic]] life. Their [[wing]]s have evolved to become flippers, useless for flight in the air. In the water, however, penguins are astonishingly agile. Penguins' swimming looks very similar to birds' flight in the air.<ref>{{cite web |url=https://www.youtube.com/watch?v=knZ6E_YV4_c |title=Penguin swimming under water, Galapagos |publisher=Youtube.com |date=April 14, 2008 |access-date=September 8, 2013 |archive-url=https://web.archive.org/web/20140608005622/http://www.youtube.com/watch?v=knZ6E_YV4_c |archive-date=June 8, 2014 |url-status=live }}</ref> Within the smooth [[plumage]] a layer of air is preserved, ensuring buoyancy. The air layer also helps insulate the birds in cold waters. On land, penguins use their [[tail]]s and wings to maintain balance for their upright stance.
All penguins are [[Countershading|countershaded]] for [[camouflage]] – that is, they have black backs and [[wing]]s with white fronts.<ref>{{cite book|last=Buskey|first=Theresa|title=The Polar Regions|editor=Alan Christopherson, M.S.|publisher=Alpha Omegan Publications, Inc|___location=804 N. 2nd Ave. E., Rock Rapids, IA|series=LIFEPAC|chapter=The Antarctic Polar Region|date=March 2001|isbn=978-1-58095-156-2}}</ref> A predator looking up from below (such as an [[orca]] or a [[leopard seal]]) has difficulty distinguishing between a white penguin belly and the reflective water surface. The dark plumage on their backs camouflages them from above.
Gentoo penguins are the fastest underwater birds in the world. They are capable of reaching speeds up to 36 km (about 22 miles) per hour while searching for food or escaping from predators. They are also able to dive to depths of 170–200 meters (about 560–660 feet).<ref>{{cite news |last1=Rafferty |first1=John |title=Gentoo Penguin |url=https://www.britannica.com/animal/gentoo-penguin |newspaper=Encyclopedia Britannica |publisher=Encyclopedia Britannica Inc. |access-date=January 20, 2021 |archive-date=January 25, 2021 |archive-url=https://web.archive.org/web/20210125133319/https://www.britannica.com/animal/gentoo-penguin |url-status=live }}</ref> The small penguins do not usually dive deep; they catch their prey near the surface in dives that normally last only one or two minutes. Larger penguins can dive deep in case of need. Emperor penguins are the world's deepest-diving birds. They can dive to depths of approximately {{convert|550|m|ft|abbr=off|sp=us}} while searching for food.<ref>{{cite web|last1=Rafferty |first1=John |title=Emperor Penguin |url=https://www.britannica.com/animal/emperor-penguin |website=Britannica Online Encyclopedia |publisher=Britannica Encyclopedia Inc. |access-date=January 20, 2021 |archive-date=January 25, 2021 |archive-url=https://web.archive.org/web/20210125140129/https://www.britannica.com/animal/emperor-penguin |url-status=live}}</ref>
Penguins either waddle on their feet or slide on their bellies across the snow while using their feet to propel and steer themselves, a movement called "tobogganing", which conserves energy while moving quickly. They also jump with both feet together if they want to move more quickly or cross steep or rocky terrain.
Penguins have an average sense of [[hearing (sense)|hearing]] for birds;<ref name="Wever">{{Cite journal
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| title = Hearing in the blackfooted penguin, ''Spheniscus demersus'', as represented by the cochlear potentials
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| volume = 63
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}}</ref> this is used by parents and chicks to locate one another in crowded [[Seabird colony|colonies]].<ref name="Jouventin">{{Cite journal
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| title = Finding a parent in a king penguin colony: The acoustic system of individual recognition
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| last2 = Aubin
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}}</ref> Their eyes are adapted for underwater vision and are their primary means of locating prey and avoiding predators; in air it has been suggested that they are [[nearsighted]], although research has not supported this hypothesis.<ref name="Sivak">{{Cite journal
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}}</ref>
[[File:Pygoscelis papua -Nagasaki Penguin Aquarium -swimming underwater-8a.jpg|thumb|left|[[Gentoo penguin]] swimming underwater at the Nagasaki Penguin Aquarium]]
Penguins have a thick layer of insulating feathers that keeps them warm in water (heat loss in water is much greater than in air). The [[emperor penguin]] has a maximum feather density of about nine feathers per square centimeter which is actually much lower than other birds that live in Antarctic environments. However, they have been identified as having at least four different ''types'' of feather: in addition to the traditional feather, the emperor has [[afterfeather]]s<!-- Can somebody make a page for this. I can not make this page myself -->, [[Down feather|plumule]]s, and [[filoplume]]s. The afterfeathers are downy plumes that attach directly to the main feathers and were once believed to account for the bird's ability to conserve heat when under water; the plumules are small down feathers that attach directly to the skin, and are much more dense in penguins than other birds; lastly the filoplumes are small (less than 1 cm long) naked shafts that end in a splay of fibers— filoplumes were believed to give flying birds a sense of where their plumage was and whether or not it needed preening, so their presence in penguins may seem inconsistent, but penguins also preen extensively.<ref>{{cite news|title=Busting Myths About Penguin Feathers|author=Ed Young|date=October 20, 2015|url=https://www.nationalgeographic.com/science/phenomena/2015/10/20/busting-myths-about-penguin-feathers/|work=National Geographic|access-date=October 7, 2018|archive-url=https://web.archive.org/web/20181007183640/https://www.nationalgeographic.com/science/phenomena/2015/10/20/busting-myths-about-penguin-feathers/|archive-date=October 7, 2018|url-status=dead}}</ref>
The emperor penguin has the largest body mass of all penguins, which further reduces relative surface area and heat loss. They also are able to control blood flow to their extremities, reducing the amount of blood that gets cold, but still keeping the extremities from freezing. In the extreme cold of the Antarctic winter, the females are at sea fishing for food, leaving the males to brave the weather by themselves. They often huddle together to keep warm and rotate positions to make sure that each penguin gets a turn in the centre of the heat pack.
Calculations of the heat loss and retention ability of marine endotherms<ref name="Calculating">{{cite journal|last1=Downhower|first1=J.F.|last2=Blumer|first2=L.S.|title=Calculating just how small a whale can be|journal=Nature|date=1988|volume=335|pages=675|doi=10.1038/335675b0|pmid=3173490|issue=#6192|bibcode=1988Natur.335..675D|s2cid=47562824}}</ref> suggest that most extant penguins are too small to survive in such cold environments.<ref name="The penguins">{{cite book|last1=Williams|first1=T.D.|title=The penguins: Spheniscidae|date=1995|publisher=Oxford University Press|___location=New York}}</ref> In 2007, Thomas and Fordyce wrote about the "heterothermic loophole" that penguins utilize in order to survive in Antarctica.<ref name="The heterothermic loophole exploited by penguins">{{cite journal |last1=Thomas |first1=D.B. |last2=Fordyce |first2=R.E. |author-link2=Ewan Fordyce |date=2007 |title=The heterothermic loophole exploited by penguins |journal=Australian Journal of Zoology |volume=55 |issue=#5 |pages=317–321 |doi=10.1071/zo07053}}</ref> All extant penguins, even those that live in warmer climates, have a counter-current heat exchanger called the humeral plexus. The flippers of penguins have at least three branches of the axillary artery, which allows cold blood to be heated by blood that has already been warmed and limits heat loss from the flippers. This system allows penguins to efficiently use their body heat and explains why such small animals can survive in the extreme cold.<ref name="Biological plasticity in penguin heat-retention structures">{{cite journal|last1=Thomas|first1=D.B.|last2=Fordyce|first2=R.E.|title=Biological plasticity in penguin heat-retention structures|journal=Anatomical Record|date=2012|volume=295|issue=#2|pages=249–256|doi=10.1002/ar.21538|pmid=22213564|s2cid=23175291|doi-access=}}</ref>
They can drink salt water because their [[supraorbital gland]] filters excess salt from the bloodstream.<ref>{{cite web |url=http://www.zoo.org/educate/fact_sheets/penguin/penguin.htm |title=Animal Fact Sheets |access-date=July 21, 2006 |url-status=dead |archive-url=https://web.archive.org/web/20060720223700/http://www.zoo.org/educate/fact_sheets/penguin/penguin.htm |archive-date=July 20, 2006 }}</ref><ref>{{cite web |url=http://www.stlzoo.org/animals/abouttheanimals/birds/penguins/humboldtpenguin.htm |title=Humboldt Penguin: Saint Louis Zoo |access-date=July 21, 2006 |url-status=dead |archive-url=https://web.archive.org/web/20060928083710/http://www.stlzoo.org/animals/abouttheanimals/birds/penguins/humboldtpenguin.htm |archive-date=September 28, 2006 }}</ref><ref>{{cite web|url=http://users.iafrica.com/b/bo/boulders/Vans%20book.htm|author=van der Merwe, H.J.|work=iafrica.com|title=African Penguins and Penguins of the World|access-date=July 21, 2006|archive-url=https://web.archive.org/web/20061012221527/http://users.iafrica.com/b/bo/boulders/Vans%20book.htm|archive-date=October 12, 2006|url-status=dead}}</ref> The salt is excreted in a concentrated fluid from the nasal passages.
The [[great auk]] of the Northern Hemisphere, now extinct, was superficially similar to penguins, and the word ''penguin'' was originally used for that bird centuries ago. They are only distantly related to the penguins, but are an example of [[convergent evolution]].<ref>[http://evo.bio.psu.edu/hedgeslab/Publications/PDF-files/128.pdf Convergence and divergence in the evolution of aquatic birds] {{webarchive|url=https://web.archive.org/web/20080529081926/http://evo.bio.psu.edu/hedgeslab/Publications/PDF-files/128.pdf |date=May 29, 2008 }} by Marcel Van Tuinen, Dave Brian Butvill, John A. W. Kirsch and S. Blair Hedges.</ref>
[[File:Penguins on Gourdin Island.jpg|thumb|An [[Isabelline (colour)|isabelline]] [[Adélie penguin]] on [[Gourdin Island]]]]
Around one in 50,000 penguins (of most species) are born with brown rather than black plumage. These are called [[Isabelline (colour)|isabelline]] penguins. Isabellinism is different from albinism. Isabelline penguins tend to live shorter lives than normal penguins, as they are not well-camouflaged against the deep and are often passed over as mates.
==Behaviour==
[[File:Pygoscelis antarctica trying to get to iceberg.wmv.OGG|thumb|[[Chinstrap penguin]]s in [[Antarctica]]]]
===Breeding===
{{Css Image Crop|Image = Brown Bluff-2016-Tabarin Peninsula–Gentoo penguin (Pygoscelis papua) 05.jpg|bSize = 450|cWidth = 220|cHeight = 250|oTop = 50|oLeft = 110|Location = right|Description = [[Gentoo penguin]] watching over a sleeping chick at [[Brown Bluff]]}}
Penguins for the most part breed in large colonies, the exceptions being the yellow-eyed and Fiordland species; these colonies may range in size from as few as 100 pairs for gentoo penguins to several hundred thousand in the case of king, macaroni and chinstrap penguins.<ref name=Will17>[[#Williams|Williams]], p. 17</ref> Living in colonies results in a high level of social interaction between birds, which has led to a large repertoire of visual as well as vocal displays in all penguin species.<ref name=Williams57>[[#Williams|Williams]], p. 57</ref> ''Agonistic'' displays are those intended to confront or drive off, or alternately appease and avoid conflict with, other individuals.<ref name=Williams57/>
Penguins form monogamous pairs for a breeding season, though the rate the same pair recouples varies drastically. Most penguins lay two eggs in a clutch, although the two largest species, the emperor and the [[king penguin]]s, lay only one.<ref name=Will23>[[#Williams|Williams]], p. 23</ref> With the exception of the emperor penguin, where the male does it all, all penguins share the [[Avian incubation|incubation]] duties.<ref>{{Cite journal | doi = 10.1080/03014223.2000.9518236| title = Prolonged foraging trips and egg desertion in little penguins (''Eudyptula minor'')| journal = New Zealand Journal of Zoology| volume = 27| issue = #4| pages = 277–289| year = 2000| last1 = Numata | first1 = M. | last2 = Davis | first2 = L. S. | last3 = Renner | first3 = M. | doi-access = free}}</ref> These incubation shifts can last days and even weeks as one member of the pair feeds at sea.
Penguins generally only lay one brood; the exception is the little penguin, which can raise two or three broods in a season.<ref>{{cite book|vauthors=Reilly PN, Balmford P |title=The Biology of Penguins|editor=Stonehouse, Bernard|publisher=Macmillan|___location=London|year=1975|pages=161–87|chapter=A breeding study of the little penguin, ''Eudyptula minor'', in Australia |isbn=978-0-333-16791-5}}</ref>
Penguin eggs are smaller than any other bird species when compared proportionally to the weight of the parent birds; at {{convert|52|g|oz|0|abbr=on}}, the little penguin egg is 4.7% of its mothers' weight, and the {{convert|450|g|lb|0|abbr=on}} emperor penguin egg is 2.3%.<ref name=Will23/> The relatively thick shell forms between 10 and 16% of the weight of a penguin egg, presumably to reduce the effects of dehydration and to minimize the risk of breakage in an adverse nesting environment.<ref>{{cite book|author=Meyer-Rochow V.B.|title=Advances in Animal Science and Zoology| editor=Jenkins Owen P.|publisher=Nova Sci Publ Inc|___location=Hauppauge, N.Y.|year=2015|pages=65–80|chapter=Examples of four incompletely resolved aspects of the biology of penguins elated to digestive and reproductive physiology, vision and locomotion | isbn =978-1-63483-328-8}}</ref> The yolk, too, is large and comprises 22–31% of the egg. Some yolk often remains when a chick is born, and is thought to help sustain the chick if the parents are delayed in returning with food.<ref name=Will24>[[#Williams|Williams]], p. 24</ref>
When emperor penguin mothers lose a chick, they sometimes attempt to "steal" another mother's chick, usually unsuccessfully as other females in the vicinity assist the defending mother in keeping her chick.<ref>{{cite news |last1=Gorvett |first1=Zaria |title=If you think penguins are cute and cuddly, you're wrong |url=http://www.bbc.com/earth/story/20151223-if-you-think-penguins-are-cute-and-cuddly-youre-wrong |access-date=March 9, 2020 |work=BBC Earth |date=December 23, 2015 |archive-date=March 8, 2020 |archive-url=https://web.archive.org/web/20200308055345/http://www.bbc.com/earth/story/20151223-if-you-think-penguins-are-cute-and-cuddly-youre-wrong |url-status=live }}</ref> In some species, such as emperor and king penguins, the chicks assemble in large groups called [[Crèche (zoology)|crèches]].
==Distribution and habitat==
{{See also|List of Sphenisciformes by population}}
Although almost all penguin species are native to the Southern Hemisphere, they are not found only in cold climates, such as [[Antarctica]]. In fact, only a few species of penguin actually live so far south. Several species live in the [[temperate]] zone;<ref>{{cite web|url=http://www.birdlife.org/worldwide/news/list-penguin-species|access-date=August 8, 2016|title=List of Penguin Species|last=Askew|first=Nick|date=June 24, 2009|publisher=BirdLife International|archive-url=https://web.archive.org/web/20160822014010/http://www.birdlife.org/worldwide/news/list-penguin-species|archive-date=August 22, 2016|url-status=live}}</ref>{{Failed verification|date=November 2020}} one, the [[Galápagos penguin]], lives as far north as the [[Galápagos Islands]], but this is only made possible by the cold, rich waters of the Antarctic [[Humboldt Current]] that flows around these islands.<ref>[[Ross Piper|Piper, Ross]] (2007), ''Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals'', [[Greenwood Press (publisher)|Greenwood Press]].</ref> Also, though the climate of the Arctic and Antarctic regions is similar, there are no penguins found in the Arctic.<ref>{{cite book|title = Book: BSCS Biology, By Arnold Brams Grobman.|url=https://books.google.com/books?id=xC-WGtA7eP8C&q=penguins+found+only+pole&pg=PA36|isbn = 9780787290085|last1 = Grobman|first1 = Arnold Brams|year = 1964| publisher=Kendall/Hunt |access-date = November 18, 2020|archive-date = October 18, 2021|archive-url=https://web.archive.org/web/20211018043947/https://books.google.com/books?id=xC-WGtA7eP8C&q=penguins+found+only+pole&pg=PA36|url-status = live}}</ref>
[[File:Gálapagos Penguins Near Isabela Island.jpg|thumb|Gálapagos Penguins near Isabela Island]]
Several authors have suggested that penguins are a good example of [[Bergmann's Rule]]<ref>{{cite journal |doi=10.1046/j.1466-822X.2002.00313.x |author=Ashton, K. |title=Patterns of within-species body size variation of birds: strong evidence for Bergmann's rule |journal=Global Ecology and Biogeography |volume=11 |year=2002 |pages=505–523 |issue=#6 |bibcode=2002GloEB..11..505A }}</ref><ref>{{cite journal |doi=10.1046/j.1365-2699.2003.00837.x |author1=Meiri, S |title=On the validity of Bergmann's rule |journal=Journal of Biogeography |volume=30 |year=2003 |pages=331–351 |issue=#3 |author2=Dayan, T. |bibcode=2003JBiog..30..331M |s2cid=11954818 |url=http://www.tau.ac.il/lifesci/zoology/members/dayan_files/articles/on_the_validity.pdf |access-date=November 13, 2014 |archive-url=https://web.archive.org/web/20150924123741/http://www.tau.ac.il/lifesci/zoology/members/dayan_files/articles/on_the_validity.pdf |archive-date=September 24, 2015 |url-status=live }}</ref> where larger-bodied populations live at higher latitudes than smaller-bodied populations. There is some disagreement about this and several other authors have noted that there are fossil penguin species that contradict this hypothesis and that ocean currents and upwellings are likely to have had a greater effect on species diversity than latitude alone.<ref>{{cite journal |doi=10.1073/pnas.0611099104 |author=Clarke, J. A.|title=Paleogene equatorial penguins challenge the proposed relationship between biogeography, diversity, and Cenozoic climate change |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=104 |issue=#28 |year=2007 |pages=11545–11550 |pmid=17601778 |pmc=1913862 |last2=Ksepka |last3=Stucchi |last4=Urbina |last5=Giannini |last6=Bertelli |last7=Narváez |last8=Boyd |bibcode=2007PNAS..10411545C |doi-access=free}}</ref><ref>{{cite journal |author=Gohlich, U. B. |title=The oldest fossil record of the extant penguin genus Spheniscus – a new species from the Miocene of Peru |url=https://www.app.pan.pl/article/item/app52-285.html |journal=Acta Palaeontologica Polonica |volume=52 |year=2007 |pages=285–298 |access-date=November 13, 2014 |archive-url=https://web.archive.org/web/20141113064147/https://www.app.pan.pl/article/item/app52-285.html |archive-date=November 13, 2014 |url-status=live }}</ref>
Major populations of penguins are found in [[Angola]], [[Antarctica]], [[Argentina]], [[Australia]], [[Chile]], [[Namibia]], [[New Zealand]], and [[South Africa]].<ref>{{cite web|archive-url=https://web.archive.org/web/20120217205921/http://www.siec.k12.in.us/west/proj/penguins/australia.html|url=http://www.siec.k12.in.us/west/proj/penguins/australia.html|title=Penguins of Australia and New Zealand |publisher=Southern Indian Education Center |access-date=September 8, 2013|archive-date=February 17, 2012 }}</ref><ref>{{cite journal |author=Jadwiszczak, P. |title=Penguin past: The current state of knowledge |url=https://www.researchgate.net/publication/230873362 |journal=Polish Polar Research |volume=30 |year=2009 |pages=3–28 |access-date=November 13, 2014 |archive-date=March 7, 2022 |archive-url=https://web.archive.org/web/20220307214202/https://www.researchgate.net/publication/230873362_Penguin_past_The_current_state_of_knowledge |url-status=live }}</ref> Satellite images and photos released in 2018 show the population of 2 million in [[France]]'s remote [[Île aux Cochons|Ile aux Cochons]] has collapsed, with barely 200,000 remaining, according to a study published in Antarctic Science.<ref>{{Cite web|url=https://www.trtworld.com/life/world-s-biggest-king-penguin-colony-shrinks-90-percent-19260|title=World's biggest king penguin colony shrinks 90 percent|website=World's biggest king penguin colony shrinks 90 percent|language=tr-TR|access-date=August 1, 2018|archive-url=https://web.archive.org/web/20180801124930/https://www.trtworld.com/life/world-s-biggest-king-penguin-colony-shrinks-90-percent-19260|archive-date=August 1, 2018|url-status=live}}</ref>
=== Conservation status ===
The majority of living penguin species have declining populations. According to the IUCN Red List, their conservation statuses range from Least Concern through to Endangered.
{| class="wikitable"
|-
! Species
!IUCN Red List Status
!Trend
!Mature Individuals
!Last assessment
|-
|[[Emperor penguin]], ''Aptenodytes forsteri''
|Near Threatened
|Decreasing
|Unknown
|2019<ref>{{cite iucn |author=BirdLife International |date=2020 |title=''Aptenodytes forsteri'' |volume=2020 |page=e.T22697752A157658053 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22697752A157658053.en |access-date=19 November 2021}}</ref>
|-
|[[King penguin]], ''Aptenodytes patagonicus''
|Least Concern
|Increasing
|
|2020<ref>{{cite iucn |author=BirdLife International. |year=2020 |title=''Aptenodytes patagonicus'' |volume=2020 |page=e.T22697748A184637776 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22697748A184637776.en |access-date=20 May 2025}}</ref>
|-
|[[Little penguin]], ''Eudyptula minor''
|Least Concern
|Stable
|469,760
|2020<ref>{{cite iucn |author=BirdLife International. |year=2020 |errata=2021 |title=''Eudyptula minor'' |volume=2020 |page=e.T22697805A202126091 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22697805A202126091.en |access-date=20 May 2025}}</ref>
|-
|[[Southern rockhopper penguin]], ''Eudyptes chrysocome''
|Vulnerable
|Decreasing
|2,500,000
|2020<ref>{{cite iucn |author=BirdLife International. |year=2020 |title=''Eudyptes chrysocome'' |volume=2020 |page=e.T22735250A182762377 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22735250A182762377.en |access-date=20 May 2025}}</ref>
|-
|[[Macaroni penguin]], ''Eudyptes chrysolophus''
|Vulnerable
|Decreasing
|
|2020<ref>{{cite iucn |author=BirdLife International. |year=2020 |title=''Eudyptes chrysolophus'' |volume=2020 |page=e.T22697793A184720991 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22697793A184720991.en |access-date=20 May 2025}}</ref>
|-
|[[Northern rockhopper penguin]], ''Eudyptes moseleyi''
|Endangered
|Decreasing
|413,700
|2020<ref>{{cite iucn |author=BirdLife International. |year=2020 |title=''Eudyptes moseleyi'' |volume=2020 |page=e.T22734408A184698049 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22734408A184698049.en |access-date=20 May 2025}}</ref>
|-
|[[Fiordland penguin]], ''Eudyptes pachyrhynchus''
|Vulnerable
|Decreasing
|12,500–50,000
|2020<ref>{{cite iucn |author=BirdLife International. |year=2020 |title=''Eudyptes pachyrhynchus'' |volume=2020 |page=e.T22697776A182279725 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22697776A182279725.en |access-date=20 May 2025}}</ref>
|-
|[[Snares penguin]], ''Eudyptes robustus''
|Vulnerable
|Stable
|63,000
|2018<ref>{{cite iucn |author=BirdLife International. |year=2018 |title=''Eudyptes robustus'' |volume=2018 |page=e.T22697782A132602343 |doi=10.2305/IUCN.UK.2018-2.RLTS.T22697782A132602343.en |access-date=20 May 2025}}</ref>
|-
|[[Royal penguin]], ''Eudyptes schlegeli'' (disputed)
|Least Concern
|Unknown
|1,340,000–1,660,000 (best estimate: 1,500,000)
|2021<ref>{{cite iucn |author=BirdLife International. |year=2022 |title=''Eudyptes schlegeli'' |volume=2022 |page=e.T22697797A210894343 |doi=10.2305/IUCN.UK.2022-1.RLTS.T22697797A210894343.en |access-date=20 May 2025}}</ref>
|-
|[[Erect-crested penguin]], ''Eudyptes sclateri''
|Endangered
|Decreasing
|150,000
|2020<ref>{{cite iucn |author=BirdLife International. |year=2020 |title=''Eudyptes sclateri'' |volume=2020 |page=e.T22697789A131879000 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22697789A131879000.en |access-date=20 May 2025}}</ref>
|-
|[[Yellow-eyed penguin]], ''Megadyptes antipodes''
|Endangered
|Decreasing
|2,600–3,000
|2020<ref>{{cite iucn |author=BirdLife International. |year=2020 |title=''Megadyptes antipodes'' |volume=2020 |page=e.T22697800A182703046 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22697800A182703046.en |access-date=20 May 2025}}</ref>
|-
|[[Adélie penguin]], ''Pygoscelis adeliae''
|Least Concern
|Increasing
|10,000,000
|2020<ref>{{cite iucn |author=BirdLife International. |year=2020 |title=''Pygoscelis adeliae'' |volume=2020 |page=e.T22697758A157660553 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22697758A157660553.en |access-date=20 May 2025}}</ref>
|-
|[[Chinstrap penguin]], ''Pygoscelis antarcticus''
|Least Concern
|Decreasing
|8,000,000
|2020<ref>{{cite iucn |author=BirdLife International. |year=2020 |title=''Pygoscelis antarcticus'' |volume=2020 |page=e.T22697761A184807209 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22697761A184807209.en |access-date=20 May 2025}}</ref>
|-
|[[Gentoo penguin]], ''Pygoscelis papua''
|Least Concern
|Stable
|774,000
|2019<ref>{{cite iucn |author=BirdLife International. |year=2020 |title=''Pygoscelis papua'' |volume=2020 |page=e.T22697755A157664581 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22697755A157664581.en |access-date=20 May 2025}}</ref>
|-
|[[African penguin]], ''Spheniscus demersus''
|Critically Endangered
|Decreasing
|19,800
|2024<ref>{{cite iucn |author=BirdLife International. |year=2024 |title=''Spheniscus demersus'' |volume=2024 |page=e.T22697810A256021744 |doi=10.2305/IUCN.UK.2024-2.RLTS.T22697810A256021744.en |access-date=20 May 2025}}</ref>
|-
|[[Humboldt penguin]], ''Spheniscus humboldti''
|Vulnerable
|Decreasing
|23,800
|2020<ref>{{cite iucn |author=BirdLife International. |year=2020 |title=''Spheniscus humboldti'' |volume=2020 |page=e.T22697817A182714418 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22697817A182714418.en |access-date=20 May 2025}}</ref>
|-
|[[Magellanic penguin]], ''Spheniscus magellanicus''
|Least Concern
|Decreasing
|2,200,000–3,200,000
|2020<ref>{{cite iucn |author=BirdLife International. |year=2020 |title=''Spheniscus magellanicus'' |volume=2020 |page=e.T22697822A157428850 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22697822A157428850.en |access-date=20 May 2025}}</ref>
|-
|[[Galápagos penguin]], ''Spheniscus mendiculus''
|Endangered
|Decreasing
|1,200
|2020<ref>{{cite iucn |author=BirdLife International. |year=2020 |title=''Spheniscus mendiculus'' |volume=2020 |page=e.T22697825A182729677 |doi=10.2305/IUCN.UK.2020-3.RLTS.T22697825A182729677.en |access-date=20 May 2025}}</ref>
|}
==Penguins and humans==
[[File:CharlesGreenwithPenguin.png|thumb|The [[Cook (profession)|cook]] on the ''[[Endurance (1912 ship)|Endurance]]'' preparing an [[emperor penguin]] for consumption.]]
[[Image:AntarcticaSummer.jpg|right|thumb|An [[Adélie penguin]] encountering a human during the Antarctic summer]]
Penguins have no special fear of humans and will often approach groups of people. This is probably because penguins have no land predators in [[Antarctica]] or the nearby offshore islands. They are preyed upon by other birds like skuas, especially in eggs and as fledglings. Other birds like petrels, sheathbills, and gulls also eat the chicks. [[Dog]]s preyed upon penguins while they were allowed in Antarctica during the age of early human exploration as [[sled dog]]s, but dogs have long since been banned from Antarctica.<ref>{{cite web |title=Removal of the sledge dogs from Antarctica |url=https://www.bas.ac.uk/about/antarctica/environmental-protection/wildlife-and-plants-2/removal-of-the-sledge-dogs/ |archive-url=https://web.archive.org/web/20141113080747/http://www.antarctica.ac.uk/about_antarctica/environment/wildlife/removal_of_sledge_dogs.php |archive-date=November 13, 2014 |publisher=Natural Environment Research Council – British Antarctic Survey |language=en-GB}}</ref> Instead, adult penguins are at risk at sea from predators such as [[shark]]s, [[orca]]s, and [[leopard seal]]s. Typically, penguins do not approach closer than around {{convert|9|ft|m|abbr=off|sp=us}}, at which point they appear to become nervous.<ref>{{Cite web|date=2011|title=beautyofbirds.com|url=https://www.beautyofbirds.com/penguins.html|url-status=bot: unknown|archive-url=https://web.archive.org/web/20210417174014/https://www.beautyofbirds.com/penguins.html|archive-date=April 17, 2021|access-date=April 17, 2021|website=Beauty Of Birds}}</ref>
In June 2011, an emperor penguin came ashore on New Zealand's [[Peka Peka|Peka Peka Beach]], {{convert|3,200|km|mi}} off course on its journey to Antarctica.<ref>{{cite news|url=http://www.3news.co.nz/Emperor-penguin-not-out-of-the-woods-yet/tabid/1160/articleID/216446/Default.aspx| work= 3 News NZ| title= Emperor penguin not out of the woods yet| date= June 25, 2011| access-date= November 21, 2012| archive-url=https://web.archive.org/web/20131210195757/http://www.3news.co.nz/Emperor-penguin-not-out-of-the-woods-yet/tabid/1160/articleID/216446/Default.aspx| archive-date= December 10, 2013| url-status= live}}</ref> Nicknamed [[Happy Feet (penguin)|Happy Feet]], after the [[Happy Feet|film of the same name]], it was suffering from heat exhaustion and had to undergo a number of operations to remove objects like driftwood and sand from its stomach.<ref>{{cite news|url=http://www.3news.co.nz/Happy-Feet-pulls-through-third-operation/tabid/1160/articleID/216660/Default.aspx| work= 3 News NZ| title= Happy Feet pulls through third operation| date= June 27, 2011| access-date= November 21, 2012| archive-url=https://web.archive.org/web/20111214073709/http://www.3news.co.nz/Happy-Feet-pulls-through-third-operation/tabid/1160/articleID/216660/Default.aspx| archive-date= December 14, 2011| url-status= live}}</ref> Happy Feet was a media sensation, with extensive coverage on TV and the web, including a live stream that had thousands of views<ref>{{cite news|url=http://www.3news.co.nz/The-truth-about-Happy-Feets-home/tabid/367/articleID/221473/Default.aspx| work= 3 News NZ| title= The truth about Happy Feet's home| date= August 8, 2011| access-date= November 21, 2012| archive-url=https://web.archive.org/web/20131210195800/http://www.3news.co.nz/The-truth-about-Happy-Feets-home/tabid/367/articleID/221473/Default.aspx| archive-date= December 10, 2013| url-status= live}}</ref> and a visit from English actor [[Stephen Fry]].<ref>{{cite news|url=http://www.3news.co.nz/Stephen-Fry-visits-Happy-Feet/tabid/1160/articleID/221822/Default.aspx| work= 3 News NZ| title= Stephen Fry visits Happy Feet| date= August 11, 2011| access-date= November 21, 2012| archive-url=https://web.archive.org/web/20120201121440/http://www.3news.co.nz/Stephen-Fry-visits-Happy-Feet/tabid/1160/articleID/221822/Default.aspx| archive-date= February 1, 2012| url-status= live}}</ref> Once he had recovered, Happy Feet was released back into the water south of New Zealand.<ref>{{cite news|url=http://www.3news.co.nz/VIDEO-Happy-Feet-starts-the-long-journey-home/tabid/1160/articleID/223894/Default.aspx| work= 3 News NZ| title= Happy Feet starts the long journey home|format=Video| date= August 29, 2011| access-date= November 21, 2012| archive-url=https://web.archive.org/web/20120202111025/http://www.3news.co.nz/VIDEO-Happy-Feet-starts-the-long-journey-home/tabid/1160/articleID/223894/Default.aspx| archive-date= February 2, 2012| url-status= live}}</ref>
===In popular culture===
{{Main|Cultural depictions of penguins}}
[[Image:Tux.svg|thumb|upright|[[Tux (mascot)|Tux]], the mascot of the [[Linux kernel]]]]
Penguins are widely considered endearing for their unusually upright, waddling [[gait]], swimming ability and (compared to other birds) lack of fear of humans. Their black-and-white plumage is often likened to a [[white tie]] suit. Some writers and artists have penguins based at the [[North Pole]], but there are no wild penguins in the [[Arctic]]. The cartoon series ''[[Chilly Willy]]'' helped perpetuate this [[myth]], as the title penguin would interact with Arctic or [[Subarctic|sub-Arctic]] species, such as [[polar bear]]s and [[walrus]]es.
Penguins have been the subject of many books and films, such as ''[[Happy Feet]]'', ''[[Surf's Up (film)|Surf's Up]]'' and ''[[Penguins of Madagascar]]'', all [[Computer-generated imagery|CGI]] films; ''[[March of the Penguins]]'', a documentary based on the [[Bird migration|migration]] process of the [[emperor penguin]]; and ''[[Farce of the Penguins]]'', a parody of the documentary. ''[[Mr. Popper's Penguins]]'' is a children's book written by Richard and Florence Atwater; it was named a [[Newbery Honor Book]] in 1939. Penguins have also appeared in a number of cartoons and television dramas, including ''[[Pingu]]'', co-created by [[Otmar Gutmann]] and Erika Brueggemann in 1990 and covering more than 100 short episodes. At the end of 2009, ''[[Entertainment Weekly]]'' put it on its end-of-the-decade "best-of" list, saying, "Whether they were walking (''March of the Penguins''), dancing (''Happy Feet''), or hanging ten (''Surf's Up''), these oddly adorable birds took flight at the box office all decade long."<ref>Geier, Thom; Jensen, Jeff; Jordan, Tina; Lyons, Margaret; Markovitz, Adam; Nashawaty, Chris; Pastorek, Whitney; Rice, Lynette; Rottenberg, Josh; Schwartz, Missy; Slezak, Michael; Snierson, Dan; Stack, Tim; Stroup, Kate; Tucker, Ken; Vary, Adam B.; Vozick-Levinson, Simon; Ward, Kate, [https://ew.com/article/2009/12/04/100-greatest-movies-tv-shows-and-more/ "The 100 Greatest Movies, TV Shows, Albums, Books, Characters, Scenes, Episodes, Songs, Dresses, Music Videos, and Trends That Entertained Us Over the Past 10 Years"] {{Webarchive|url=https://web.archive.org/web/20140415144141/http://www.ew.com/ew/article/0,,20324138_2,00.html |date=April 15, 2014 }}. ''Entertainment Weekly''. December 11, 2009 (1079/1080):74-84</ref>
A video game called ''[[Pengo (video game)|Pengo]]'' was released by [[Sega]] in 1982. Set in Antarctica, the player controls a penguin character who must navigate mazes of ice cubes. The player is rewarded with cut-scenes of animated penguins marching, dancing, saluting and playing [[peekaboo]]. Several remakes and enhanced editions have followed, most recently in 2012. Penguins are also sometimes depicted in music.<ref>Shuker, R. (2012). ''Understanding popular music culture''. Routledge.{{ISBN|9781317440895}}{{page needed|date=November 2021}}</ref>
In 1941, [[DC Comics]] introduced the avian-themed character of the [[Penguin (character)|Penguin]] as a [[supervillain]] adversary of the [[superhero]] [[Batman]] (''Detective Comics'' #58). He became one of the most enduring enemies in [[List of Batman family enemies#Classic rogues gallery|Batman's rogues gallery]]. In the 60s ''[[Batman (TV series)|Batman]]'' TV series, as played by [[Burgess Meredith]], he was one of the most popular characters, and in [[Tim Burton]]'s reimagining of the story, the character played by [[Danny Devito]] in the 1992 film ''[[Batman Returns]]'', employed an actual army of penguins (mostly [[African penguin]]s and [[king penguin]]s).
Several pro, minor, college and high school sport teams in the [[United States]] have named themselves after the species, including the [[Pittsburgh Penguins]] team in the [[National Hockey League]] and the [[Youngstown State Penguins]] in [[college athletics]].
Penguins featured regularly in the cartoons of U.K. cartoonist [[Steve Bell (cartoonist)|Steve Bell]] in his strip in ''[[The Guardian]]'' newspaper, particularly during and following the [[Falklands War]]. [[Opus the Penguin]], from the cartoons of [[Berkeley Breathed]], is also described as hailing from the Falklands. Opus was a comical, "existentialist" penguin character in the cartoons ''[[Bloom County]]'', ''[[Outland (comic strip)|Outland]]'' and ''[[Opus (comic strip)|Opus]]''. He was also the star in the animated Christmas TV special ''[[A Wish for Wings That Work]]''.
In the mid-2000s, penguins became one of the most publicized species of animals that form lasting [[Homosexuality in animals#Penguins|homosexual couples]]. A [[Children's literature|children's book]], ''[[And Tango Makes Three]]'', was written about [[Roy and Silo|one such penguin family]] in the [[Central Park Zoo|New York Zoo]].
==References==
{{Reflist|30em|refs=
<ref name=Baker>{{cite journal|ref=Baker|doi=10.1098/rspb.2005.3260|title=Multiple gene evidence for expansion of extant penguins out of Antarctica due to global cooling|journal=Proceedings of the Royal Society B: Biological Sciences|volume=273|issue=#1582|pages=11–7|year=2006|last1=Baker|first1=A. J|last2=Pereira|first2=S. L.|last3=Haddrath|first3=O. P|last4=Edge|first4=K.-A.|pmid=16519228|pmc=1560011}}</ref>
<ref name="Clarke">{{cite journal |author1=Clarke, Julia A. |author2=Olivero, Eduardo B. |author3=Puerta, Pablo |name-list-style=amp |year=2003 |title=Description of the earliest fossil penguin from South America and first Paleogene vertebrate locality of Tierra Del Fuego, Argentina |journal=American Museum Novitates |issue=3423 |pages=1–18 |url=http://digitallibrary.amnh.org/dspace/bitstream/2246/2788/1/N3423.pdf |doi=10.1206/0003-0082(2003)423<0001:dotefp>2.0.co;2 |hdl=2246/2788 |s2cid=19041678 |access-date=January 4, 2007 |archive-url=https://web.archive.org/web/20070724203258/http://digitallibrary.amnh.org/dspace/bitstream/2246/2788/1/N3423.pdf |archive-date=July 24, 2007 |url-status=live }}</ref>
<ref name="Crofford10">{{cite book| last = Crofford| first = Emily| title = Gone Forever: The Great Auk| place = New York| publisher = Crestwood House| year = 1989| isbn = 978-0-89686-459-7| page = [https://archive.org/details/greatauk0000crof/page/10 10]|url=https://archive.org/details/greatauk0000crof/page/10}}</ref>
<ref name="Jadwiszczak">{{cite journal|author=Jadwiszczak, Piotr|year=2006|title=Eocene penguins of Seymour Island, Antarctica: taxonomy|journal=Polish Polar Research|volume=27|issue=#1|pages=3–62|url=http://www.polish.polar.pan.pl/ppr27/ppr27-003.pdf|access-date=February 2, 2007|archive-url=https://web.archive.org/web/20070724203259/http://www.polish.polar.pan.pl/ppr27/ppr27-003.pdf|archive-date=July 24, 2007|url-status=dead}}</ref>
}}
==Bibliography==
* {{cite book |ref=Williams |url-access=registration |author1=Williams |author2=Tony D. |year=1995 |url=https://archive.org/details/penguinssphenisc0000will |title=The Penguins – Spheniscidae |place=Oxford |publisher=[[Oxford University Press]] |isbn=978-0-19-854667-2}}
==External links==
{{Sister project links|b=no|commons=Spheniscidae|d=y|n=yes|q=no|s=no|species=Sphenisciformes|v=no}}
{{Library resources box}}
* [https://web.archive.org/web/20070628185533/http://news.nationalgeographic.com/news/2007/06/070625-giant-penguins.html Two new fossil penguin species found in Peru]. news.nationalgeographic.com
* [http://www.pinguins.info/ Information about penguins at pinguins.info]
* [https://web.archive.org/web/20060217020708/http://www.itis.usda.gov/ Integrated Taxonomic Information System] (archived February 17, 2006)
* [https://archive.today/20060315235518/http://www.70south.com/resources/antarctic-animals/antarctic-penguins Penguin information on 70South] (archived March 15, 2006)
* [http://www.penguinpage.net/ Penguin research projects on the web]
* [https://web.archive.org/web/20151227155646/http://ibc.lynxeds.com/family/penguins-spheniscidae Penguin videos and photos] on the Internet Bird Collection (archived December 27, 2015)
* [http://www.penguinworld.com/ Penguin World]
* [https://web.archive.org/web/20080905012627/http://www.teara.govt.nz/EarthSeaAndSky/BirdsOfSeaAndShore/Penguins/en Penguins] in [[Te Ara: The Encyclopedia of New Zealand]] the [[Encyclopedia of New Zealand]] (archived September 5, 2008)
* [https://web.archive.org/web/20131017221136/http://seaworld.org/animal-info/info-books/penguin/index.htm Seaworld Penguin Information] (archived October 17, 2013)
* [http://www.nwf.org/News-and-Magazines/National-Wildlife/Birds/Archives/2010/Lessons-in-a-Land-of-Wind-and-Ice.aspx "Lessons in a Land of Wind and Ice" from ''National Wildlife'' Magazine 1/15/2010]
* [https://curiouspenguins.com Curious Penguins]
* [http://dsc.discovery.com/tv/frozen-planet/penguin-cam/ Live 24/7 camera inside a penguin habitat]
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{{Birds}}
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[[Category:Articles containing video clips]]
[[Category:Flightless birds]]
[[Category:Penguins| ]]
[[Category:Seabirds]]
[[Category:Spheniscidae| ]]
[[Category:Spheniscinae| ]]
[[Category:Sphenisciformes| ]]
[[Category:Danian first appearances]]
[[Category:Taxa named by Charles Lucien Bonaparte]]
[[Category:Extant Danian first appearances]]
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