Rorqual

{{Short description|Family of cetacean mammals}} {{Automatic taxobox | name = Rorquals<ref name=msw3>{{MSW3 Cetacea|id=14300010}}</ref> | fossil_range = {{fossil range|15.97|0|Miocene–Recent|ref=<ref>{{cite web|url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=42977 |title=Family Balaenopteridae Gray 1864 (rorqual) |work=Fossilworks |access-date=9 April 2018}}</ref>}} | image = Anim1754_-_Flickr_-_NOAA_Photo_Library.jpg | image_caption = Blue whale, ''Balaenoptera musculus'' | image2 = | image2_caption = Humpback whale song | display_parents = 2 | taxon = Balaenopteridae | authority = {{Harvnb|Gray|1864}} | type_genus = ''Balaenoptera'' | type_genus_authority = Lacépède, 1804 | subdivision_ranks = Extant genera | subdivision = ''Balaenoptera'' ''Megaptera'' | synonyms = Eschrichtiidae? Ellerman & Morrison-Scott 1951 Rhachianectidae Weber 1904 | range_map = File:Balaenopteridae distribution.png | range_map_caption = Balaenopteridae distribution (in blue) }}

'''Rorquals''' ({{IPAc-en|ˈ|r|ɔr|k|w|əl|z}}) are the largest group of baleen whales, comprising the family '''Balaenopteridae''', which contains nine extant species in two genera. They include the largest animal ever known to have lived, the blue whale, which can reach {{convert|180|t|ST}}, and the fin whale, which reaches {{convert|120|t|ST}}; the smallest of the group, the northern minke whale, reaches {{convert|9|t|ST|-1}}.

Rorquals take their name from French {{lang|fr|rorqual}}, which derives from the Norwegian word {{lang|no|{{linktext|røyrkval}}}}: the first element {{lang|no|røyr}} originated from the Old Norse name for this type of whale, {{lang|non|reyðr}},<ref>{{OED|rorqual}}: "{{abbr|ad.|adaptation of}} {{abbr|Norw.|Norwegian}} ''røyrkval'', {{abbr|repr.|representing}} ON. *''røyðar''-, OIcel. ''reyðar-hvalr'', {{abbr|f.|from}} ''{{linktext|reyður|reyðr}}'' the specific name + ''hvalr'' whale."</ref> probably related to the Norse word for "red", and the second from the Norse word ''hvalr'' meaning "whale" in general.<ref>{{cite book|title=The Century Dictionary|url=https://books.google.com/books?id=2Fok2OmCP74C&pg=PA5228|year=1895|page=5228}}</ref> The family name Balaenopteridae is from the type genus, ''Balaenoptera''.

== Characteristics == All members of the family have a series of longitudinal folds of skin running from below the mouth back to the navel (except the sei whale and common minke whale, which have shorter grooves). These furrows allow the mouth to expand immensely when feeding.<ref name="Worlds">{{cite book|title=The World's Whales: The Complete Illustrated Guide| editor-first1= Stanley M. |editor-last1=Minasian |editor-first2= Kenneth C. |editor-last2= Balcomb|editor-first3= Larry |editor-last3=Foster|page=18|year=1984|publisher=The Smithsonian Institution|place=New York|isbn=978-0-89599-014-3}}</ref> These "pleated throat grooves" distinguish balaenopterids from other whales.<ref name="Worlds" />

Rorquals are slender and streamlined in shape, compared with their relatives the right whales, and most have narrow, elongated flippers. They have a dorsal fin, situated about two-thirds the way back. Most rorquals feed by gulping in water, and then pushing it out through the baleen plates with their tongue; the exception is the gray whale, which gulps in and filters large amounts of marine sediments from the seafloor. They feed on crustaceans, such as krill, but also on various fish, such as herrings and sardines.<ref name=EoM>{{cite book|title= The Encyclopedia of Mammals|last= Gambell|first= Ray|editor-last1= Macdonald|editor-first1= D|year= 1984|publisher= Facts on File|location= New York|pages= [https://archive.org/details/encyclopediaofma00mals_0/page/222 222–225]|isbn= 978-0-87196-871-5|url= https://archive.org/details/encyclopediaofma00mals_0/page/222}}</ref>

Gestation in rorquals lasts 11–12 months, so that both mating and birthing occur at the same time of year. Cows give birth to a single calf, which is weaned after 6–12 months, depending on species.<ref name=EoM /> Of some species, adults live in small groups, or "pods" of two to five individuals. For example, humpback whales have a fluid social structure, often engaging behavioral practices in a pod, other times being solitary.

== Distribution and habitat == Distribution is worldwide: the blue, fin, humpback, and the sei whales are found in all major oceans; the common (northern) and Antarctic (southern) minke whale species are found in all the oceans of their respective hemispheres; either of Bryde's whale and Eden's whale occur in the Atlantic, Pacific, and Indian oceans, being absent only from the cold waters of the Arctic and Antarctic; and the gray whale is found in the northern Pacific Ocean, although it was also found in the Atlantic Ocean in historic times.<ref>{{Cite web|title=All About Baleen Whales {{!}} SeaWorld Parks & Entertainment|url=https://seaworld.org/animals/all-about/baleen-whales|access-date=2021-01-23|website=seaworld.org|language=en}}</ref> Rice's whale has the smallest distribution of rorquals and possibly baleen whales in general, being endemic to a small portion of the Gulf of Mexico west of the Florida peninsula and south of Alabama and the Florida panhandle, although it likely formerly had a much wider distribution in the Gulf.<ref>{{Cite journal|last1=Rosel|first1=Patricia E.|last2=Wilcox|first2=Lynsey A.|last3=Yamada|first3=Tadasu K.|last4=Mullin|first4=Keith D.|title=A new species of baleen whale (Balaenoptera) from the Gulf of Mexico, with a review of its geographic distribution|url=https://repository.library.noaa.gov/view/noaa/47278/noaa_47278_DS1.pdf|journal=Marine Mammal Science|year=2021|volume=37|issue=2|pages=577–610|language=en|doi=10.1111/mms.12776|bibcode=2021MMamS..37..577R |issn=1748-7692}}</ref>

Most rorquals are strictly oceanic: the exceptions are the gray whale, Bryde's whale, Eden's whale, and Rice's whale (which are usually found close to shore all year round)<ref>{{Cite web|last=Handbook|first=Whale Watching|date=2021-01-22|title=Bryde's Whale|url=https://wwhandbook.iwc.int/en/species/brydes-whale|access-date=2021-01-23|website=Whale Watching Handbook|language=en}}</ref> and the humpback whale (which is oceanic but passes close to shore when migrating). It is the largest and the smallest types — the blue whale and Antarctic minke whale — that occupy the coldest waters in the extreme south; the fin whale tends not to approach so close to the ice shelf; the sei whale tends to stay further north again. (In the northern hemisphere, where the continents distort weather patterns and ocean currents, these movements are less obvious, although still present.) Within each species, the largest individuals tend to approach the poles more closely, while the youngest and fittest ones tend to stay in warmer waters before leaving on their annual migration.

Most rorquals breed in tropical waters during the winter, then migrate back to the polar feeding grounds rich in plankton and krill for the short polar summer.

== Feeding habits == [[File:Anim1076 - Flickr - NOAA Photo Library.jpg|thumb|Humpback feeding on young pollock off Alaska]]

As well as other methods, rorquals obtain prey by lunge-feeding on bait balls.<ref name="Stuff123">{{cite book| last1= Reeves |first1= RR |last2= Stewart |first2= BS |last3= Clapham |first3= PJ |last4= Powell |first4=JA |year= 2002 |url= https://books.google.com/books?id=5CYXAQAAIAAJ&q=%22National+Audubon+Society+Guide+to+Marine+Mammals+of+the+World%22 |title= National Audubon Society Guide to Marine Mammals of the World |publisher= Chanticleer Press |isbn= 0-375-41141-0|page=233}}</ref> Lunge feeding is an extreme feeding method, where the whale accelerates to a high velocity and then opens its mouth to a large gape angle. This generates the water pressure required to expand its mouth and engulf and filter a huge amount of water and fish.<ref name="Stuff123" /> In contrast to typical lunge feeding, Gray whales employ a unique suction feeding strategy to capture prey near or on the sea bottom.<ref>{{Cite journal| doi = 10.1111/mms.13210| issn = 1748-7692| volume = 41| issue = 2| pages = –13210| last1 = Colson| first1 = Kate M.| last2 = Pirotta| first2 = Enrico| last3 = New| first3 = Leslie| last4 = Cade| first4 = David E.| last5 = Calambokidis| first5 = John| last6 = Bierlich| first6 = K. C.| last7 = Bird| first7 = Clara N.| last8 = Ajó| first8 = Alejandro Fernandez| last9 = Hildebrand| first9 = Lisa| last10 = Trites| first10 = Andrew W.| last11 = Torres| first11 = Leigh G.| title = Using accelerometry tags to quantify gray whale foraging behavior| journal = Marine Mammal Science| date = 2025| article-number = e13210| bibcode = 2025MMamS..4113210C| doi-access = free| hdl = 10023/30998| hdl-access = free}}</ref>

Rorquals have a number of anatomical features that enable them to do this, including bilaterally separate mandibles, throat pleats that can expand to huge size, and a unique sensory organ consisting of a bundle of mechanoreceptors that helps their brains to coordinate the engulfment action.<ref>{{cite journal |author1-link=Nicholas Pyenson| last1 = Pyenson | first1 = N.D. |last2= Goldbogen |first2= J.A. |last3= Vogl |first3= A.W. |last4= Szathmary |first4= G |last5= Drake |first5= R.L. |last6= Shadwick |first6= R.E. | title = Discovery of a sensory organ that coordinates lunge feeding in rorqual whales | journal = Nature | volume = 485 | issue = 7399 | pages = 498–501 | publisher = Nature Publishing Group | year = 2012 | doi = 10.1038/nature11135 | pmid=22622577| bibcode = 2012Natur.485..498P | s2cid = 1200222 }}</ref> Furthermore, their large nerves are flexible so that they can stretch and recoil.<ref name="McSpadden 2015">{{cite magazine | last=McSpadden | first=Kevin | title=Gigantic Whales Eat Thanks To 'Bungee-Cord' Nerves | magazine=Time | date=5 May 2015 | url=https://time.com/3846646/whales-biology-blue-whales-nerves-nervous-system/ | access-date=6 May 2015}}</ref> In fact, they give rorquals the ability to open their mouths so wide that they would be capable of taking in water at volumes greater than their own sizes. These nerves are packed into a central core area that is surrounded by elastin fibers. Opening the mouth causes the nerves to unfold, and they snap back after the mouth is closed.<ref name="McSpadden 2015" /> According to Potvin and Goldbogen, lunge feeding in rorquals represents the largest biomechanical event on Earth.<ref>{{cite journal| last1= Potvin |first1= J |last2= Goldbogen |first2= J.A. |year= 2009 |title= Passive versus active engulfment: verdict from trajectory simulations of lunge-feeding fin whales ''Balaenoptera physalus'' |journal= J. R. Soc. Interface |volume= 6 |number= 40 |pages= 1005–1025| doi= 10.1098/rsif.2008.0492 |pmid=19158011 |pmc=2827442}}</ref>

== Taxonomy == [[File:Rorqual Cladogram.svg|thumb|Cladogram of the family Balaenopteridae using complete mtDNA sequences and short interspersed repetitive element (SINE) insertion data.]]

[[File:Plesiobalaenoptera hubachi.jpg|thumb|Skeleton of the extinct ''Plesiobalaenoptera hubachi'' at the Museum für Naturkunde, Berlin]]

Formerly, the rorqual family Balaenopteridae was split into two subfamilies, the Balaenopterinae and the Megapterinae, with each subfamily containing one genus, ''Balaenoptera'' and ''Megaptera'', respectively. However, the phylogeny of the various rorqual species shows the current division is paraphyletic, and in 2005, the division into subfamilies was dropped.<ref name="Deméré 2005">{{cite journal |last1 = Deméré |first1 = T.A. |last2 = Berta |first2 = A. |last3 = McGowen |first3 = M.R. |year = 2005 |title = The taxonomic and evolutionary history of fossil and modern balaenopteroid mysticetes |journal = Journal of Mammalian Evolution |volume = 12 |issue = 1/2 |pages = 99–143 |doi = 10.1007/s10914-005-6944-3|s2cid = 90231 }}</ref> Two genetic studies, one in 2018 and one in 2020, suggest that the gray whale (''Eschrichtius robustus'') be counted among the rorquals, being more derived than the two minke whales but basal to the humpback whale, fin whale, and the other taxa classified in ''Balaenoptera''.<ref>{{cite journal |title=Whole-genome sequencing of the blue whale and other rorquals finds signatures for introgressive gene flow |journal=Science Advances |year=2018 |volume=4 |issue=4 |article-number=eaap9873 |first1=Úlfur |last1=Árnason |first2=Fritjof |last2=Lammers |first3=Vikas |last3=Kumar |first4=Maria A. |last4=Nilsson |first5=Axel |last5=Janke |doi=10.1126/sciadv.aap9873|pmc=5884691 |pmid=29632892 |bibcode=2018SciA....4.9873A }}</ref><ref>{{Cite journal|last1=McGowen|first1=Michael R|last2=Tsagkogeorga|first2=Georgia|last3=Álvarez-Carretero|first3=Sandra|last4=dos Reis|first4=Mario|last5=Struebig|first5=Monika|last6=Deaville|first6=Robert|last7=Jepson|first7=Paul D|last8=Jarman|first8=Simon|last9=Polanowski|first9=Andrea|last10=Morin|first10=Phillip A|last11=Rossiter|first11=Stephen J|date=2019-10-21|title=Phylogenomic Resolution of the Cetacean Tree of Life Using Target Sequence Capture|journal=Systematic Biology|volume=69|issue=3|pages=479–501|doi=10.1093/sysbio/syz068|issn=1063-5157|pmc=7164366|pmid=31633766}}</ref>

The discovery of a new species of balaenopterid, Omura's whale (''Balaenoptera omurai''), was announced in November 2003, which looks similar to, but smaller than, the fin whale; individuals of this species were found in Indo-Pacific waters. The discovery of the highly endangered Rice's whale was announced in 2021 after a genetic study found it to be distinct from Bryde's whale; this species is known from a small portion of the northeastern Gulf of Mexico.<ref>{{Cite web|last=Fisheries|first=NOAA|date=2021-01-19|title=Gulf of Mexico Bryde's Whale {{!}} NOAA Fisheries|url=https://www.fisheries.noaa.gov/species/gulf-mexico-brydes-whale|access-date=2021-01-22|website=NOAA|language=en}}</ref>

=== Extant species === * Family '''Balaenopteridae''': Rorquals<ref>{{cite web |title=List of Marine Mammal Species and Subspecies |url=https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/ |website=Society for Marine Mammalogy |access-date=January 18, 2022 |language=en |date=2021}}</ref> ** ''Balaenoptera'' *** Fin whale, ''Balaenoptera physalus'' **** Northern fin whale, ''Balaenoptera physalus physalus'' **** Southern fin whale, ''Balaenoptera physalus quoyi'' *** Sei whale, ''Balaenoptera borealis'' *** Bryde's whale, ''Balaenoptera edeni'' **** Eden's whale, ''Balaenoptera edeni edeni'' ***Rice's whale, ''Balaenoptera ricei'' *** Blue whale, ''Balaenoptera musculus'' **** Pygmy blue whale, ''Balaenoptera musculus brevicauda'' *** Common minke whale, ''Balaenoptera acutorostrata'' *** Antarctic minke whale, ''Balaenoptera bonaerensis'' *** Omura's whale, ''Balaenoptera omurai'' ** ''Megaptera'' *** Humpback whale, ''Megaptera novaeangliae''

=== Fossil genera === **{{Extinct}}''Archaebalaenoptera'' **{{Extinct}}''Archaeschrichtius'' **{{Extinct}}''Cetotheriophanes'' ** {{Extinct}}''Diunatans'' **{{Extinct}}''Eschrichtioides'' **{{Extinct}}''Gricetoides'' **{{Extinct}}''Incakujira'' **{{Extinct}}''Miobalaenoptera'' ** {{Extinct}}''Nehalaennia'' **{{Extinct}}''Parabalaenoptera'' ** {{Extinct}}''Plesiobalaenoptera'' ** {{Extinct}}''Plesiocetus'' ** {{Extinct}}''Praemegaptera'' ** {{Extinct}}''Protororqualus''[[File:Incakujira anilliodefuego.jpg|thumb|''Incakujira anilliodefuego'' paratype]]

=== Alternative generic taxonomy for living rorquals === In 2012, the following alternate taxonomy was presented:<ref>{{cite journal|first1=A. |last1= Hassanin |first2= F. |last2= Delsuc |first3= A. |last3= Rpiquet |first4=C. |last4= Hammer |first5= B. J. |last5= Vuuren |first6= C. |last6= Matthee |first7= M. |last7= Ruiz-Garcia |first8= F. |last8= Gatzeflis |first9= V. |last9= Areskoug |first10= T. T. |last10= Nguyen |first11= A. |last11= Couloux |year= 2012 |title= Pattern and timing of diversification of Cetartiodactyla (Mammalia, Laurasiatheria), as revealed by a comprehensive analysis of mitochondrial genomes |journal= Comptes Rendus Biologies |volume= 335 |issue= 1 |pages= 32–50 |doi=10.1016/j.crvi.2011.11.002 |pmid=22226162|doi-access= free }}</ref> * ''Balaenoptera'' ** Fin whale, ''Balaenoptera physalus'' * ''Megaptera'' ** Humpback whale, ''Megaptera novaeangliae'' * ''Pterobalaena'' ** Common minke whale, ''Pterobalaena acutorostrata'' ** Antarctic minke whale, ''Pterobalaena bonaerensis'' * ''Rorqualus'' ** Sei whale, ''Rorqualus borealis'' ** Bryde's whale, ''Rorqualus brydei'' ** Eden's whale, ''Rorqualus edeni'' ** Blue whale, ''Rorqualus musculus'' ** Omura's whale, ''Rorqualus omurai''

== References == {{reflist|group=Committee on Taxonomy, 2021}}

=== Notes === {{Reflist|30em}}

=== Sources === {{Refbegin}} * {{Cite journal | last = Gray | first = J. E. | author-link = John Edward Gray | title = Notes on the Whalebone-Whales; with a Synopsis of the Species | year = 1864 | journal = The Annals and Magazine of Natural History | volume = 14 | issue = 83 | pages = 345–353 | url = https://www.biodiversitylibrary.org/partpdf/61505 | doi = 10.1080/00222936408681724 }} {{Refend}}

== External links == * {{Commons category-inline|Balaenopteridae}} * {{Wikispecies-inline|Balaenopteridae}} * {{Cite EB1911|wstitle=Rorqual|short=x}}

{{Cetacea|M.}} {{portalbar|Cetaceans|Mammals|Animals|Biology|Marine Life}} {{Taxonbar|from=Q232829}} {{Authority control}}

Category:Rorquals Category:Baleen whales Category:Taxa named by John Edward Gray