Editing Cave bear (section)

==Taxonomy==
[[File:Cave bear AMNH.jpg|thumb|upright|Rearing ''Ursus spelaeus'' skeleton at the [[AMNH]]]]
Cave bear skeletons were first described in 1774 by Johann Friedrich Esper, in his book ''Newly Discovered Zoolites of Unknown Four Footed Animals''. While scientists at the time considered that the skeletons could belong to [[ape]]s, [[canid]]s, [[felid]]s, or even [[dragon]]s or [[unicorn]]s, Esper postulated that they actually belonged to [[polar bear]]s. Twenty years later, [[Johann Christian Rosenmüller]], an [[anatomist]] at [[Leipzig University]], gave the species its binomial name. The bones were so numerous that most researchers had little regard for them. During [[World War I]], with the scarcity of [[phosphate]] dung, earth from the caves where cave bear bones occurred was used as a source of phosphates. When the "dragon caves" in [[Austria]]’s [[Duchy of Styria|Styria]] region were exploited for this purpose, only the skulls and leg bones were kept.<ref name="Brunner2007">{{cite book|author=Bernd Brunner|title=Bears: A Brief History|url=https://books.google.com/books?id=1W98s7aVy8cC&pg=PA41|year=2007|publisher=Yale University Press|isbn=978-0-300-12299-2|page=41}}</ref>

Many caves in [[Central Europe]] and [[North America]]  have skeletons of cave bears inside, such as the ''Heinrichshöhle'' in [[Hemer, Germany|Hemer]] and the ''[[Dechen Cave|Dechenhöhle]]'' in [[Iserlohn]], [[Germany]]. A complete skeleton, five complete skulls, and 18&nbsp;other bones were found inside [[Kletno Bear Cave]], in 1966 in [[Poland]].<ref>{{cite book |author=Praca Zbiorowa |title=Jaskinia Niedźwiedzia w Kletnie. Badanie i udostępnianie |publisher=Polska Akademia Nauk, Ossolineum |location=Wrocław |year=1989 |isbn=8304030373 |language=pl}} with summary {{in lang|en}}</ref> In [[Romania]], in a cave called [[Bears' Cave]], 140&nbsp;cave bear skeletons were discovered in 1983.<ref>[https://web.archive.org/web/20070202235231/http://www.personal.psu.edu/users/w/x/wxk116/cavebears/ Cave Bears]. Jan Kowalski. psu.edu</ref>

Remains assigned to "cave bears" ''sensu lato'' from the Late Pleistocene exhibit a strong degree of morphological and size variability, and have often been assigned to their own species, including ''[[Ursus rossicus]]'' (Eastern Europe, Central Asia and Siberia)'', [[Ursus ingressus]]'' (Central Europe to the Urals), ''[[Ursus kanivetz]],'' (Urals) ''[[Ursus kudarensis]]'' (the Caucasus), ''[[Ursus eremus]]'' (Central Europe, possibly a subspecies of ''U. spelaeus'' s.s.) and ''Ursus spelaeus'' sensu stricto (Western, Central and Southeast Europe).<ref name=":0" /><ref name=":1">{{Cite journal |last=Barlow |first=Axel |last2=Paijmans |first2=Johanna L.A. |last3=Alberti |first3=Federica |last4=Gasparyan |first4=Boris |last5=Bar-Oz |first5=Guy |last6=Pinhasi |first6=Ron |last7=Foronova |first7=Irina |last8=Puzachenko |first8=Andrey Y. |last9=Pacher |first9=Martina |last10=Dalén |first10=Love |last11=Baryshnikov |first11=Gennady |last12=Hofreiter |first12=Michael |date=2021-04-26 |title=Middle Pleistocene genome calibrates a revised evolutionary history of extinct cave bears |url=https://linkinghub.elsevier.com/retrieve/pii/S096098222100138X |journal=Current Biology |language=en |volume=31 |issue=8 |pages=1771–1779.e7 |doi=10.1016/j.cub.2021.01.073}}</ref> These populations/species show considerable genetic divergence from each other, (with genetic divergences estimated at hundreds of thousands to a million years)<ref name=":1" /> though whether these species should be regarded as synonyms of ''U. speleus'' is debated.<ref name=":0">{{cite journal |last1=Galdies |first1=Johann |title=The bears of the European steppe: a review |journal=Quaternaire |date=2022-03-01 |volume=33 |issue=1 |pages=47–62 |doi=10.4000/quaternaire.16605 |url=https://journals.openedition.org/quaternaire/16605 |issn=1142-2904 |access-date=2025-02-07}}</ref>

===Evolution===
Both the cave bear and the brown bear are thought to be descended from the [[Plio-Pleistocene]] Etruscan bear (''[[Ursus etruscus]]'')<ref name=Kurten1976>{{cite book |author=Kurtén, B. |year=1976 |title=The Cave Bear Story: Life and death of a vanished animal |publisher=Columbia University Press |location=New York, NY}}</ref><ref name=Rabader2000>{{cite book |vauthors=Rabeder G, Nagel D, Pacher M |year=2000 |title=Der Höhlenbär. Species 4 |publisher=Thorbecke Verlag |location=Stuttgart, DE}}</ref><ref>{{cite book |vauthors=Argant A, Crégut-Bonnoure E |year=1996 |contribution=Famille des Ursidae |editor1=Guérin, C. |editor2=Patou-Mathis, M. |title=Les grands mammiferes Plio-Pleistocenes d'Europe |pages=167–177 |publisher=Masson |location=Paris, FR}}</ref> that lived about 5.3&nbsp;[[Mya (unit)|Mya]] to 100,000&nbsp;years ago. The last common ancestor of cave bears and brown bears lived between 1.2&ndash;1.4&nbsp;Mya.<ref name="Loreille2001">{{Cite journal |author=Loreille, O. |display-authors=etal |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 |bibcode=2001CBio...11..200L |doi=10.1016/S0960-9822(01)00046-X |pmid=11231157 |doi-access=free}}</ref> Middle Pleistocene remains of the cave bear lineage are assigned to ''[[Ursus deningeri]]'' (Deninger's bear),<ref name=":0" /> which is known from remains spanning from Europe to China.<ref>{{Cite journal |last1=Jiangzuo |first1=Qigao |last2=Wagner |first2=Jan |last3=Chen |first3=Jin |last4=Dong |first4=Cuiping |last5=Wei |first5=Jianhua |last6=Ning |first6=Juan |last7=Liu |first7=Jinyi |date=2018-11-01 |title=Presence of the Middle Pleistocene cave bears in China confirmed – Evidence from Zhoukoudian area |url=https://linkinghub.elsevier.com/retrieve/pii/S0277379118303354 |journal=Quaternary Science Reviews |language=en |volume=199 |pages=1–17 |doi=10.1016/j.quascirev.2018.09.012}}</ref> The transition between Deninger's bear and the cave bear is given as the last interglacial, although the boundary between these forms is arbitrary, and intermediate or transitional [[taxa]] have been proposed, e.g. ''Ursus spelaeus deningeroides'',<ref name=Argant1991>{{Cite journal|author=Argant, A. |title=Carnivores quaternaires de Bourgogne |year=1991 |journal=Documents des Laboratoires de Géologie de la Faculté des Sciences de Lyon |volume=115 |pages=1–301}}</ref> while other authorities consider both taxa to be chronological variants of the same species.<ref name=MazzaRustioni1994>{{Cite journal |author1=Mazza, P. |author2=Rustioni, M. |title=On the phylogeny of Eurasian bears |year=1994 |journal=Palaeontographica Abteilung A |volume=230 |issue=1–3 |pages=1–32|doi=10.1127/pala/230/1994/1 |bibcode=1994PalAA.230....1M |s2cid=247508689 }}</ref>

Cave bears found anywhere will vary in age, thus facilitating investigations into evolutionary trends. The three anterior [[premolar]]s were gradually reduced, then disappeared, possibly in response to a largely vegetarian diet. In a fourth of the skulls found in the ''Conturines'', the third premolar is still present, while more [[Synapomorphy|derived]] specimens elsewhere lack it. The last remaining premolar became conjugated with the true [[Molar (tooth)|molars]], enlarging the crown and granting it more cusps and cutting borders. This phenomenon, called ''molarization'', improved the [[mastication]] capacities of the molars, facilitating the processing of tough vegetation. This allowed the cave bear to gain more energy for hibernation, while eating less than its ancestors.<ref>{{cite web |url=http://www.altabadia.it/orsispelei/evoluzione_i.htm |title=Gli orsi spelèi delle Conturines / Ursus Spelaeus |website=Altabadia.it |access-date=2011-09-26 |df=dmy-all}}</ref>

In 2005, scientists recovered and [[DNA sequencing|sequenced]] the [[nuclear DNA]] of a cave bear that lived between 42,000 and 44,000 years ago. The procedure used genomic DNA extracted from one of the animal's [[teeth]]. Sequencing the DNA directly (rather than first replicating it with the [[polymerase chain reaction]]), the scientists recovered 21 cave bear [[gene]]s from remains that did not yield significant amounts of DNA with traditional techniques.<ref name="Noonan2005">{{Cite journal |author=Noonan, James P. |display-authors=etal |year=2005 |title=Genomic Sequencing of Pleistocene Cave Bears |url=https://digital.library.unt.edu/ark:/67531/metadc786565/ |journal=[[Science (journal)|Science]] |volume=309 |issue=5734 |pages=597–599 |bibcode=2005Sci...309..597N |doi=10.1126/science.1113485 |pmid=15933159 |s2cid=34704597 |doi-access=free}}</ref> This study confirmed and built on results from a previous study using [[mitochondrial DNA]] extracted from cave bear remains ranging from 20,000 to 130,000 years old.<ref name=Loreille2001/> Both show that the cave bear was more closely related to the [[brown bear]] and [[polar bear]] than it was to the [[American black bear]], but had split from the brown bear lineage before the distinct eastern and western brown bear lineages diversified, and before the split of brown bears and polar bears. The [[Genetic divergence|divergence]] date estimate of cave bears and brown bears is about 1.2–1.4&nbsp;Mya.<ref name=Loreille2001/> However, a recent study showed that both species had some hybridization between them.<ref>{{Cite journal|last1=Barlow|first1=Axel|last2=Cahill|first2=James A.|last3=Hartmann|first3=Stefanie|last4=Theunert|first4=Christoph|last5=Xenikoudakis|first5=Georgios|last6=Fortes|first6=Gloria G.|last7=Paijmans|first7=Johanna L. A.|last8=Rabeder|first8=Gernot|last9=Frischauf|first9=Christine|date=27 August 2018|title=Partial genomic survival of cave bears in living brown bears|journal=[[Nature Ecology & Evolution]]|language=En|volume=2|issue=10|pages=1563–1570|doi=10.1038/s41559-018-0654-8|issn=2397-334X|url=https://escholarship.org/content/qt6qr394rt/qt6qr394rt.pdf?t=poma92|pmid=30150744|pmc=6590514|bibcode=2018NatEE...2.1563B }}</ref>