Editing Brown bear (section)

==Evolution and taxonomy==

===Taxonomy and subspecies===
{{main|Subspecies of brown bear}}
[[File:Eurasian brown bear (Ursus arctos arctos) female 1.jpg|thumb|Adult female [[Eurasian brown bear]], the [[nominate subspecies]]|alt=A bear in a wooded area|left]]

[[Carl Linnaeus]] scientifically described the species under the name ''Ursus arctos'' in the 1758 edition of ''[[Systema Naturae]]''.<ref>{{Cite book |last=Linnaeus |first=Carl |chapter-url=https://gdz.sub.uni-goettingen.de/id/PPN362053006?tify=%7B%22pages%22:%5B51%5D,%22pan%22:%7B%22x%22:0.524,%22y%22:0.878%7D,%22view%22:%22scan%22,%22zoom%22:0.831%7D |title=Caroli Linnæi ó. Systema naturæ per regna tria naturæ, secundum classses, ordines, genera, species, cum characteribus, differentiis, synonymis, locis |year=1758 |page=47|location=Stockholm|publisher=Lars Salvius|language=la|chapter=''Ursus arctos''}}</ref> Brown bear taxonomy and subspecies classification has been described as "formidable and confusing", with few authorities listing the same set of subspecies.<ref>{{citation |last1=Wilson |first1=D. E. |last2=Ruff |first2=S. |year=1999 |title=The Smithsonian Book of North American Mammals |publisher=[[Smithsonian Institution Press]] |location=Washington, D.C.|pages=160–201}}</ref> There are hundreds of obsolete brown-bear subspecies. As many as 90 subspecies have been proposed.<ref name=Harris>{{cite news|last1=Harris|first1=Arthur H.|url=https://www.researchgate.net/publication/236842872|title=Pleistocene Vertebrates of Arizona, New Mexico, and Trans-Pecos Texas|date=2013|publisher=UTEP Biodiversity Collections, University of Texas at El Paso}}</ref><ref name=Storer1955>{{cite book |last1=Storer |first1=T. I. |last2=Tevis |first2=L. P. |title=California Grizzly |url=https://books.google.com/books?id=1QVZFQu01KcC&pg=PA149 |url-access=registration |year=1996 |publisher=[[University of California Press]] |location=[[Berkeley, California|Berkeley, CA]] |isbn=978-0-520-20520-8 |pages=[https://archive.org/details/californiagrizzl00stor/page/335 335], 42–187 |access-date=18 November 2019 |archive-date=2 February 2024 |archive-url=https://web.archive.org/web/20240202162031/https://books.google.com/books?id=1QVZFQu01KcC&pg=PA149#v=onepage&q&f=false |url-status=live }} [https://archive.org/details/californiagrizzl00stor Alt URL]</ref> A 2008 [[DNA analysis]] identified as few as five main [[clade]]s, which comprise all extant brown bear species, while a 2017 [[Phylogenetics|phylogenetic]] study revealed nine clades, including one representing polar bears.<ref name="ReferenceA">{{cite journal |author1=Calvignac, S. |author2=Hughes, S. |author3=Tougard, C. |author4=Michaux, J. |author5=Thevenot, M. |author6=Philippe, M. |author7=Hamdine, W.|author8=Hanni, C.|title=Ancient DNA evidence for the loss of a highly divergent brown bear clade during historical times |journal=[[Molecular Ecology]] |year=2008 |volume=17 |issue=8 |pages=1962–1970 |doi=10.1111/j.1365-294x.2008.03631.x |pmid=18363668|bibcode=2008MolEc..17.1962C |s2cid=23361337 |url=https://hal.archives-ouvertes.fr/hal-00287307/file/calvignac2008.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://hal.archives-ouvertes.fr/hal-00287307/file/calvignac2008.pdf |archive-date=2022-10-09 |url-status=live }}</ref><ref name="lan">{{cite journal |author1=Lan, T. |author2=Gill, S. |author3=Bellemain, E. |author4=Bischof, R. |author5=Zawaz, M. A. |author6=Lindqvist, C. |year=2017 |title=Evolutionary history of enigmatic bears in the Tibetan Plateau–Himalaya region and the identity of the yeti |journal=Proceedings of the Royal Society B: Biological Sciences |volume=284 |issue=1,868 |pages=20,171,804 |doi=10.1098/rspb.2017.1804 |pmid=29187630 |pmc=5740279}}</ref> {{as of|2005}}, 15 extant, or recently extinct, subspecies were recognized by the general scientific community.<ref name=MSW3>{{MSW3 Wozencraft | id =14000970 | pages = 588–589|heading = ''Ursus arctos''}}</ref>

DNA analysis shows that, apart from recent, human-caused [[population fragmentation]],<ref>{{Cite journal |last1=Proctor |first1=Michael F. |last2=Paetkau |first2=David |last3=Mclellan |first3=Bruce N. |last4=Stenhouse |first4=Gordon B. |last5=Kendall |first5=Katherine C. |last6=Mace |first6=Richard D. |last7=Kasworm |first7=Wayne F. |last8=Servheen |first8=Christopher |last9=Lausen |first9=Cori L. |year=2012 |title=Population fragmentation and inter-ecosystem movements of grizzly bears in western Canada and the northern United States |journal=[[Wildlife Monographs]] |volume=180 |issue=1 |pages=1–46 |doi=10.1002/wmon.6 |bibcode=2012WildM.180....1P |s2cid=16790669 |issn=1938-5455}}</ref> brown bears in North America are generally part of a single interconnected population system, with the exception of the population (or subspecies) in the [[Kodiak Archipelago]], which has probably been isolated since the end of the [[Last Glacial Period|last Ice Age]].<ref>{{Cite journal |last1=Strobeck |first1=Curtis |last2=Craighead |first2=Lance |last3=Clarkson |first3=Peter L. |last4=Waits |first4=Lisette P. |last5=Paetkau |first5=David |date=1 December 1997 |title=An Empirical Evaluation of Genetic Distance Statistics Using Microsatellite Data From Bear (Ursidae) Populations |url=http://www.genetics.org/content/147/4/1943 |journal=[[Genetics (journal)|Genetics]] |volume=147 |issue=4 |pages=1943–1957 |doi=10.1093/genetics/147.4.1943 |issn=0016-6731 |pmid=9409849 |pmc=1208359 |access-date=29 January 2019 |archive-date=29 January 2019 |archive-url=https://web.archive.org/web/20190129235849/http://www.genetics.org/content/147/4/1943 |url-status=live }}</ref><ref name="Waits">{{cite journal |author=Waits, L. P. |year=1998 |title=Mitochondrial DNA Phylogeography of the North American Brown Bear and Implications for Conservation |journal=[[Conservation Biology (journal)|Conservation]] |volume=12 |issue=2 |pages=408–417 |doi=10.1111/j.1523-1739.1998.96351.x |bibcode=1998ConBi..12..408W |s2cid=86172292 |display-authors=etal}}</ref> These data demonstrate that ''U. a. gyas'', ''U. a. horribilis'', ''U. a. sitkensis'', and ''U. a. stikeenensis'' are not distinct or cohesive groups, and would more accurately be described as [[Ecotype|ecotypes]]. For example, brown bears in any particular region of the Alaska coast are more closely related to adjacent grizzly bears than to distant populations of brown bears.<ref>{{Cite journal|last1=Paetkau|first1=D.|last2=Shields|first2=G. F.|last3=Strobeck|first3=C.|date=1998|title=Gene flow between insular, coastal and interior populations of brown bears in Alaska|journal=Molecular Ecology|volume=7|issue=#10|pages=1283–1292|issn=0962-1083|pmid=9787441|doi=10.1046/j.1365-294x.1998.00440.x|bibcode=1998MolEc...7.1283P |s2cid=21848010}}</ref>

The history of the bears of the [[Alexander Archipelago]] is unusual in that these island populations carry polar bear DNA, presumably originating from a population of polar bears that was left behind at the end of the [[Pleistocene]], but have since been connected with adjacent mainland populations through the movement of males, to the point where their nuclear genomes indicate more than 90% brown bear ancestry.<ref name="Shapiro_al.2013">{{Cite journal |last1=Shapiro |first1=Beth |last2=Slatkin |first2=Montgomery |last3=Stirling |first3=Ian |last4=John |first4=John St. |last5=Salamzade |first5=Rauf |last6=Ovsyanikov |first6=Nikita |last7=Jay |first7=Flora |last8=Stiller |first8=Mathias |last9=Fulton |first9=Tara L. |date=14 March 2013 |title=Genomic Evidence for Island Population Conversion Resolves Conflicting Theories of Polar Bear Evolution |journal=[[PLOS Genetics]] |volume=9 |issue=3 |page=e1003345 |doi=10.1371/journal.pgen.1003345 |issn=1553-7404 |pmc=3597504 |pmid=23516372 |doi-access=free |bibcode=2013PLOSG...9.3345C }}</ref> [[MtDNA]] analysis revealed that brown bears are apparently divided into five different clades, some of which coexist or co-occur in different regions.<ref name="Servheen" />

===Evolution===
The brown bear is one of eight extant species in the [[bear|bear family Ursidae]] and of six extant species in the subfamily [[Ursinae]]. {{Phylogeny/Ursidae}}

The brown bear is thought to have evolved from the [[Etruscan bear]] (''Ursus etruscus'') in Asia during the [[early Pliocene]].<ref name="evolution" /><ref>{{cite journal |author=Pérez-Hidalgo, T. |year=1992 |title=The European descendants of ''Ursus etruscus'' C. Cuvier (Mammalia, Carnivora, Ursidae) |journal=Boletín del Instituto Geológico y Minero de España |volume=103 |issue=4 |pages=632–642 |url=http://oa.upm.es/4004/2/TORRES_ART_1992_02.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://oa.upm.es/4004/2/TORRES_ART_1992_02.pdf |archive-date=2022-10-09 |url-status=live}}</ref> A genetic analysis indicated that the brown bear lineage diverged from the [[cave bear]] species-complex approximately 1.2–1.4&nbsp;million years ago, but did not clarify if ''U. savini'' persisted as a [[paraspecies]] for the brown bear before perishing.<ref name="Loreille">{{cite journal |pmid=11231157 |year=2001 |title=Ancient DNA analysis reveals divergence of the cave bear, ''Ursus spelaeus'', and brown bear, ''Ursus arctos'', lineages |journal=[[Current Biology]] |volume=11 |issue=3 |pages=200–203 |last1=Loreille |first1=O. |last2=Orlando |first2=L. |last3=Patou-Mathis |first3=M. |last4=Philippe |first4=M. |last5=Taberlet |first5=P. |last6=Hänni |first6=C. |doi=10.1016/s0960-9822(01)00046-x|s2cid=14645603 |doi-access=free |bibcode=2001CBio...11..200L }}</ref> The oldest brown bear fossils occur in Asia from about 500,000 to 300,000 years ago.<ref name="Herrero, S. 1972">{{cite journal|author=Herrero, S. |year=1972|title=Aspects of evolution and adaptation in American black bears (''Ursus americanus'' Pallas) and brown and grizzly bears (''U. arctos'' Linne.) of North America|journal=Bears: Their Biology and Management|volume=2|pages= 221–231|url=http://www.bearbiology.com/fileadmin/tpl/Downloads/URSUS/Vol_2/Herrero.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.bearbiology.com/fileadmin/tpl/Downloads/URSUS/Vol_2/Herrero.pdf |archive-date=2022-10-09 |url-status=live|doi=10.2307/3872586|jstor=3872586}}</ref><ref>{{Cite journal |last1=Kosintsev |first1=Pavel A. |last2=Bocherens |first2=Hervé |last3=Kirillova |first3=Irina V. |last4=Levchenko |first4=Vladimir A. |last5=Zazovskaya |first5=Elya P. |last6=Trofimova |first6=Svetlana S. |last7=Lan |first7=Tianying |last8=Lindqvist |first8=Charlotte |date=5 December 2024 |title=Palaeoecological and genetic analyses of Late Pleistocene bears in Asiatic Russia |journal=[[Boreas (journal)|Boreas]] |language=en |volume=51 |issue=2 |pages=465–480 |doi=10.1111/bor.12570 |issn=0300-9483 |doi-access=free }}</ref> They entered Europe 250,000 years ago and North Africa shortly after.<ref name="evolution" /> Brown bear remains from the Pleistocene period are common in the [[British Isles]], where, amongst other factors, they may have contributed to the extinction of [[cave bear]]s (''Ursus spelaeus'').<ref name="evolution2">{{cite journal |last1=McLellan |first1=Bruce |last2=Reiner |first2=David C. |year=1994 |title=A Review of bear evolution |url=http://www.bearbiology.com/fileadmin/tpl/Downloads/URSUS/Vol_9/McLellan_Reiner_Vol_9.pdf |url-status=live |journal=Int. Conf. Bear Res. And Manage |volume=9 |issue=1 |pages=85–96 |doi=10.2307/3872687 |jstor=3872687 |archive-url=https://ghostarchive.org/archive/20221009/http://www.bearbiology.com/fileadmin/tpl/Downloads/URSUS/Vol_9/McLellan_Reiner_Vol_9.pdf |archive-date=2022-10-09}}</ref>

Brown bears first emigrated to North America from Eurasia via [[Beringia]] during the [[Illinoian (stage)|Illinoian Glaciation]].<ref name=":19">{{Cite journal |last1=Salis |first1=Alexander T. |last2=Bray |first2=Sarah C. E. |last3=Lee |first3=Michael S. Y. |last4=Heiniger |first4=Holly |last5=Barnett |first5=Ross |last6=Burns |first6=James A. |last7=Doronichev |first7=Vladimir |last8=Fedje |first8=Daryl |last9=Golovanova |first9=Liubov |last10=Harington |first10=C. Richard |last11=Hockett |first11=Bryan |last12=Kosintsev |first12=Pavel |last13=Lai |first13=Xulong |last14=Mackie |first14=Quentin |last15=Vasiliev |first15=Sergei |date=December 2022 |title=Lions and brown bears colonized North America in multiple synchronous waves of dispersal across the Bering Land Bridge |url=https://onlinelibrary.wiley.com/doi/10.1111/mec.16267 |journal=Molecular Ecology |language=en |volume=31 |issue=24 |pages=6407–6421 |doi=10.1111/mec.16267 |pmid=34748674 |bibcode=2022MolEc..31.6407S |issn=0962-1083|hdl=11343/299180 |hdl-access=free }}</ref> Genetic evidence suggests that several brown bear populations migrated into North America, aligning with the glacial cycles of the Pleistocene. The founding population of most North American brown bears arrived first, with the genetic lineage developing around ~177,000 [[Before Present|BP]]. Genetic divergences suggest that brown bears first migrated south during [[Marine Isotope Stage 5|MIS-5]] (~92,000–83,000 BP), upon the opening of the ice-free corridor,<ref name=":19" /><ref name=":14">{{Cite journal |last1=Kubiak |first1=Cara |last2=Grimes |first2=Vaughan |last3=Van Biesen |first3=Geert |last4=Keddie |first4=Grant |last5=Buckley |first5=Mike |last6=Macdonald |first6=Reba |last7=Richards |first7=M. P. |date=2022-06-27 |title=Dietary niche separation of three Late Pleistocene bear species from Vancouver Island, on the Pacific Northwest Coast of North America |url=https://onlinelibrary.wiley.com/doi/10.1002/jqs.3451 |journal=Journal of Quaternary Science |language=en |volume=38 |pages=8–20 |doi=10.1002/jqs.3451 |issn=0267-8179 |s2cid=250134103 |access-date=2 January 2024 |archive-date=31 October 2023 |archive-url=https://web.archive.org/web/20231031102205/https://onlinelibrary.wiley.com/doi/10.1002/jqs.3451 |url-status=live }}</ref><ref name=":156">{{Cite journal |last1=Steffen |first1=Martina L. |last2=Fulton |first2=Tara L. |date=2018-02-01 |title=On the association of giant short-faced bear (Arctodus simus) and brown bear (Ursus arctos) in late Pleistocene North America |journal=Geobios |volume=51 |issue=1 |pages=61–74 |bibcode=2018Geobi..51...61S |doi=10.1016/j.geobios.2017.12.001}}</ref> After a local extinction in Beringia ~33,000 BP, two new but closely related lineages repopulated Alaska and northern Canada from Eurasia after the [[Last Glacial Maximum]] (>25,000 BP).<ref name=":19" />

Brown-bear fossils discovered in [[Ontario]], [[Ohio]], [[Kentucky]], and [[Labrador Peninsula|Labrador]] show that the species occurred farther east than indicated in historic records.<ref name="evolution">{{cite journal |last1=McLellan |first1=Bruce |last2=Reiner |first2=David C. |year=1994 |title=A Review of bear evolution |url=http://www.bearbiology.com/fileadmin/tpl/Downloads/URSUS/Vol_9/McLellan_Reiner_Vol_9.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.bearbiology.com/fileadmin/tpl/Downloads/URSUS/Vol_9/McLellan_Reiner_Vol_9.pdf |archive-date=2022-10-09 |url-status=live |journal=Int. Conf. Bear Res. And Manage |volume=9 |issue=1 |pages=85–96 |doi=10.2307/3872687 |jstor=3872687}}</ref> In North America, two types of the subspecies ''Ursus arctos horribilis'' are generally recognized—the coastal brown bear and the inland grizzly bear.<ref name="pasitschniak-arts1993mamsp"></ref>

===Hybrids===
{{See also|Grizzly–black bear hybrid|Grizzly–polar bear hybrid}}
[[File:To replace picture in 'Ursid hybrid'.jpg|thumb|Possible [[grizzly bear|grizzly]]–[[American black bear|black bear]] hybrid in the [[Yukon]] Territory|alt=A photo of a bear walking in tall grass]]

A grizzly–polar bear hybrid is a rare [[ursid hybrid]] resulting from a crossbreeding of a brown bear with a [[polar bear]]. It has occurred both in captivity and in the wild. In 2006, the occurrence of this hybrid was confirmed by testing the [[DNA]] of a strange-looking bear that had been shot in the Canadian [[Arctic]], and seven more hybrids have since been confirmed in the same region, all descended from a single female polar bear.<ref>{{Cite journal|last1=Richardson|first1=Evan|last2=Branigan|first2=Marsha|last3=Paetkau|first3=David|last4=Pongracz|first4=Jodie D.|date=31 May 2017|title=Recent Hybridization between a Polar Bear and Grizzly Bears in the Canadian Arctic|journal=Arctic|volume=70|issue=#2|pages=151–160|doi=10.14430/arctic4643|issn=1923-1245|doi-access=free}}</ref> Previously, the hybrid had been produced in [[zoo]]s and was considered a "[[Cryptozoology|cryptid]]" (a hypothesized animal for which there is no scientific proof of existence in the wild).<ref>{{Cite journal |last1=Janke |first1=Axel |last2=Nilsson |first2=Maria A. |last3=Kolter |first3=Lydia |last4=Pfenninger |first4=Markus |last5=Bidon |first5=Tobias |last6=Lammers |first6=Fritjof |last7=Kumar |first7=Vikas |date=19 April 2017 |title=The evolutionary history of bears is characterized by gene flow across species |journal=[[Scientific Reports]] |volume=7 |pages=46,487 |doi=10.1038/srep46487 |issn=2045-2322 |pmc=5395953 |pmid=28422140 |bibcode=2017NatSR...746487K}}</ref> Analyses of the genomes of bears have shown that [[introgression]] between species was widespread during the evolution of the genus ''Ursus'',<ref>{{Cite journal |doi=10.1126/science.1216424 |pmid=22517859 |title=Nuclear Genomic Sequences Reveal that Polar Bears Are an Old and Distinct Bear Lineage |journal=Science |volume=336 |issue=6079 |pages=344–347 |year=2012 |last1=Hailer |first1=F. |last2=Kutschera |first2=V. E. |last3=Hallstrom |first3=B. M. |last4=Klassert |first4=D. |last5=Fain |first5=S. R. |last6=Leonard |first6=J. A. |last7=Arnason |first7=U. |last8=Janke |first8=A. |bibcode=2012Sci...336..344H |hdl=10261/58578|s2cid=12671275 |hdl-access=free }}</ref> including the introgression of polar-bear DNA introduced to brown bears during the Pleistocene.<ref>{{Cite journal |doi=10.1073/pnas.1210506109 |title=Polar and brown bear genomes reveal ancient admixture and demographic footprints of past climate change |journal=Proceedings of the National Academy of Sciences |volume=109 |issue=36 |pages=E2382–E2390 |year=2012 |last1=Miller |first1=W. |last2=Schuster |first2=S. C. |last3=Welch |first3=A. J. |last4=Ratan |first4=A. |last5=Bedoya-Reina |first5=O. C. |last6=Zhao |first6=F. |last7=Kim |first7=H. L. |last8=Burhans |first8=R. C. |last9=Drautz |first9=D. I. |last10=Wittekindt |first10=N. E. |last11=Tomsho |first11=L. P. |last12=Ibarra-Laclette |first12=E. |last13=Herrera-Estrella |first13=L. |last14=Peacock |first14=E. |last15=Farley |first15=S. |last16=Sage |first16=G. K. |last17=Rode |first17=K. |last18=Obbard |first18=M. |last19=Montiel |first19=R. |last20=Bachmann |first20=L. |last21=Ingolfsson |first21=O. |last22=Aars |first22=J. |last23=Mailund |first23=T. |last24=Wiig |first24=O. |last25=Talbot |first25=S. L. |last26=Lindqvist |first26=C. |bibcode=2012PNAS..109E2382M |pmid=22826254 |pmc=3437856|doi-access=free }}</ref>