Examine individual changes

'{{italictitle}}{{Taxobox | name = Short-faced bears | fossil_range = Middle to Late [[Pleistocene]] | image = ArctodusSimusSkeleton.jpg | image_width = 250px | image_caption = http://faculty.etsu.edu/schubert/cavepage/bigbear.JPG | regnum = [[Animal]]ia | phylum = [[Chordate|Chordata]] | classis = [[Mammalia]] | ordo = [[Carnivora]] | familia = [[Ursidae]] | subfamilia = [[Tremarctinae]] | tribus = [[Tremarctini]] | genus = [[extinction|†]]'''''Arctodus''''' | genus_authority = [[Joseph Leidy|Leidy]], 1854 | subdivision_ranks = Species | subdivision = *†''A. simus'' <small>Cope, 1897</small> *†''A. pristinus'' }} '''''Arctodus''''' ([[Greek language|Greek]], "bear tooth") — known as the '''short-faced bear''' or '''bulldog bear''' — is an extinct genus of [[bear]] endemic to [[North America]] during the [[Pleistocene]] ~3.0 Ma.—11,000 years ago, existing for approximately three million years. ''Arctodus simus'' may have once been Earth's largest mammalian, terrestrial carnivore. It was the most common of early North American bears, being most abundant in [[California]].<ref name="Bearalmanac">{{cite book | author = Brown, Gary | title = Great Bear Almanac | year = 1996 | isbn = 1558214747 | page = 340}}</ref> ==Taxonomy, classification and evolution== [[Image:Arctodus simus Sergiodlarosa.jpg|thumb|Restoration of ''Arctodus simus'']] The short-faced bears belonged to a group of bears known as the [[Tremarctinae|tremarctine]] bears or running bears, which have been found in the [[Americas]] and [[Europe]]. The earliest member of the Tremarctinae was ''[[Plionarctos]] edensis'', which lived in [[Indiana]] and [[Tennessee]] during the [[Miocene]] [[epoch (geology)|Epoch]] (10 [[Mega-annum|mya]]). This [[genus]] is considered ancestral to ''Arctodus'', as well as to the modern [[Spectacled Bear|spectacled bear]], ''Tremarctos ornatus''. ''[[Tremarctos floridanus]]'' was a contemporary. Although the early history of ''Arctodus'' is poorly known, it evidently became widespread in North America by the [[Kansan glaciation|Kansan age]] (about 800,000 years ago). A related group of bears are the South American genus ''[[Arctotherium]]'', had which similar short faced adaptions and reached even greater size. A fossil of ''Arctotherium augustidens'' ({{ma|2.0|0.5|Ma.}}) species first found in 1935 in [[Argentina]] was re-examined in 2011, and found to be the largest bear to ever exist, weighing an estimated {{Convert|1600|kg|lb|abbr=on}}. The species was likely at least {{Convert|3.4|m|ft|abbr=on}} tall, and its [[humerus]] was similar in size to an elephant's.<ref>{{cite news|last=Dell'Amore|first=Christine|title=Biggest Bear Ever Found—"It Blew My Mind," Expert Says|url=http://news.nationalgeographic.com/news/2011/02/110203-biggest-bear-largest-giant-short-faced-animals-science/|accessdate=6 February 2011|newspaper=National Geographic Daily News|date=February 3, 2011}}</ref> ==Species== [[Image:ArctodusSimusReconstruct.jpg|thumb|''A. simus'' compared to a human in size]] '''''Arctodus simus''''' ({{ma|2.0|1.9|Ma.|1}}), {{Convert|110.2|kg|lb|abbr=on|sigfig=2}} and {{Convert|800|kg|lb|abbr=on|sigfig=2}} as noted by Legendre and Roth, inhabiting a generally more northern and larger range. It was native to [[Prehistory|prehistoric]] [[North America]] from about 800,000 years ago, and became extinct about 12,500 years ago. It has been found from as far north as [[List of rivers of Alaska|Ikpikpuk River]], [[Alaska]]<ref>C. S. Churcher, A. V. Morgan, and L. D. Carter. 1993. Arctodus simus from the Alaskan Arctic Slope. Canadian Journal of Earth Sciences 30(5):1007-1013, collected by A. V. Morgan</ref><ref>M. L. Cassiliano. 1999. Biostratigraphy of Blancan and Irvingtonian mammals in the Fish Creek-Vallecito Creek section, southern California, and a review of the Blancan-Irvingtonian boundary. Journal of Vertebrate Paleontology 19(1):169-186</ref> to [[Lowndes County, Mississippi]]. It is one of the largest bears in the fossil record and was among the largest mammalian land predators of all time. The [[type specimen]] came from Potter Creek Cave in Shasta County, California.<ref>COPE, E. D. 1879. The cave bear of California. American Naturalist, 13:791.</ref> Males from the Yukon region - the largest representatives of the species - would have stood about {{convert|1.80|m|ft|abbr=on}} at the shoulder (on all fours), {{convert|4|m|ft|abbr=on}} upright and may have weighed about {{Convert|800|kg|lb|abbr=on|sigfig=2}}.<ref>Christiansen, P. 1999b. What size were ''Arctodus simus'' and ''Ursus spelaeus'' (Carnivora: Ursidae)? Annales Zoologici Fennici 36:93–102</ref> ''Arctodus simus'' was the largest carnivorous mammal that ever lived in North America. '''''Arctodus pristinus''''' ({{ma|3|2.2|Ma.|1}}), a species with 2 specimens weighing {{Convert|500.7|kg|lb|abbr=on|sigfig=2}} and {{Convert|63.6|kg|lb|abbr=on|sigfig=2}}<ref>S. Legendre and C. Roth. 1988. Correlation of carnassial tooth size and body weight in recent carnivores (Mammalia). Historical Biology 1(1):85-98</ref> inhabiting more southern areas from northern [[Texas]] to [[New Jersey]] in the east, [[Aguascalientes]], [[Mexico]]<ref>I. Ferrusquia-Villafranca. 1978. Bol Univ Nac Aut Mex Inst Geol 101:193-321</ref> to the southwest, and with large concentrations in [[Florida]], the oldest from the Santa Fe River 1 site of [[Gilchrist County, Florida|Gilchrist County, Florida paleontological sites]]. ==Dietary habits== [[Image:Arctodus skull.jpg|thumb|''Arctodus'' skull]] Researchers disagree on the diet of ''Arctodus''. Analysis of ''Arctodus'' bones showed high concentrations of [[nitrogen-15]], a stable nitrogen isotope accumulated by meat-eaters, with no evidence of ingestion of vegetation. Based upon this evidence ''A. simus'' was highly [[carnivorous]], and as an adult would have required {{Convert|16|kg|lb|1}} of flesh per day to survive.<ref name=natgeog>National Geographic Channel, 16 September 2007, ''Prehistoric Predators: Short-faced bear'', interview with Dr. Paul Matheus</ref><ref name="Simus">{{cite web | url =http://www.wc.adfg.state.ak.us/index.cfm?adfg=wildlife_news.view_article&articles_id=232&issue_id=41| title = The Biggest Bear ... Ever | work = Nancy Sisinyak | publisher = ''Alaska Fish and Wildlife News'' | accessdate = 2008-01-12}}</ref> One theory of its predatory habits envisions ''Arctodus simus'' as a brutish predator that overwhelmed the large mammals of the Pleistocene with its great physical strength. However, despite being very large its limbs were too gracile for such an attack strategy. Alternatively, long legs and speed ({{Convert|50|-|70|km/h|mph|sigfig=1}}) may have allowed it to run down Pleistocene herbivores such as [[Przewalski's horse|steppe horses]] and [[saiga antelope]]s in a [[cheetah]]-like fashion.<ref>U.S. [[National Park Service]] paleontologist Greg McDonald.</ref> However, in this scenario, the bear’s sheer physical mass would be a handicap. ''Arctodus'' skeletons do not articulate in a way that would have allowed for quick turns, an ability required of any predator that survives by killing agile prey.<ref name="Simus"/> Dr. Paul Matheus, paleontologist at the [[University of Alaska Fairbanks]], determined that ''Arctodus''' moved in a [[Horse gait#Pace|pacing]] motion like a [[camel]], horse, and modern bears, making it built more for endurance than for great speed.<ref name="Simus"/> ''Arctodus simus'', according to these arguments, was ill-equipped to be an active predator, leading some to conclude that it was a [[kleptoparasite]],<ref name="Simus"/> using its enormous size to intimidate smaller predators such as [[Dire wolf|dire wolves]], ''[[Smilodon]]'' and [[American lion]]s from their kills. Recently, closer dietary research on the giant short-faced bear as well as the [[cave bear]] suggests that both bears were omnivores like most modern bears, and that the former did eat plants depending on availability.<ref name="ScienceDaily">ScienceDaily, 13 April 2009. {{cite web | url = http://www.sciencedaily.com/releases/2009/04/090408170815.htm| title= Prehistoric Bears Ate Everything And Anything, Just Like Modern Cousins | publisher = ScienceDaily | accessdate = 2009-04-13}}</ref> ==Extinction== The giant short-faced bear became extinct about 12,000 years ago, perhaps partly because some of its large prey died out earlier, and partly also because of competition with the smaller, more [[Omnivore|omnivorous]] brown bears that entered North America from [[Eurasia]]. Since its demise coincides with the development of the [[Clovis culture|Clovis]] technology and improved hunting techniques by humans in North America, hunting pressure may also have contributed to its extinction, both directly (human hunting) or indirectly (due to the depletion of other large mammals which it may have followed to scavenge kills or depended upon as prey). ==Popular culture references== ''Arctodus simus'', the giant short-faced bear, was featured in the ninth episode of ''[[Jurassic Fight Club]]'', where it fought with an [[American lion]] over a [[steppe bison]] kill made by the lion. The battle was based on a fossil find from the [[Pit Cave|Natural Trap Cave]], in the U.S. state of [[Wyoming]]. The program used the fossil evidence to predict who would win the fight. In the end, the ''Arctodus'' won by throwing the 750-pound lion into the enormous cave, where it died from the fall. ==See also== *[[Pleistocene megafauna]] == References == {{reflist}} [[Category:Bears]] [[Category:Prehistoric bears]] [[Category:Pleistocene extinctions]] [[Category:Prehistoric mammals of North America]] [[Category:Megafauna of North America]] [[Category:Extinct animals of the United States]] [[ar:أركتدس سيمس]] [[bg:Късомуцунеста мечка]] [[ca:Arctodus simus]] [[cs:Medvěd krátkočelý]] [[de:Kurznasenbär]] [[es:Arctodus simus]] [[eu:Aurpegi motzeko hartz]] [[fr:Arctodus simus]] [[it:Arctodus simus]] [[lv:Milzu īssejas lācis]] [[hu:Rövidfejű medve]] [[mk:Arctodus simus]] [[nl:Kortsnuitbeer]] [[pl:Niedźwiedź krótkopyski]] [[pt:Arctodus]] [[ru:Короткомордый медведь]] [[sk:Arctodus simus]] [[sl:Orjaški ozkoglavi medved]] [[fi:Tylppäkuonokarhu]] [[sv:Arctodus simus]] [[zh:巨型短面熊]]'