Editing Bear (section)

==Behavior and ecology==
[[File:Bear tracks (5062843250).jpg|thumb|right|[[American black bear]] tracks at [[Superior National Forest]], [[Minnesota]], U.S.]]

Brown and American black bears are generally [[diurnality|diurnal]], meaning that they are active for the most part during the day, though they may forage substantially by night.<ref>{{cite journal |last1=Klinka |first1=D. R. |last2=Reimchen |first2=T. E. |title=Nocturnal and diurnal foraging behaviour of brown bears ( Ursus arctos ) on a salmon stream in coastal British Columbia |url=http://web.uvic.ca/~reimlab/noctdibrbear.pdf |journal=Canadian Journal of Zoology |volume=80 |issue=8 |pages=1317–1322 |date=2002 |doi=10.1139/Z02-123 |bibcode=2002CaJZ...80.1317K |access-date=2017-01-07 |archive-url=https://web.archive.org/web/20170812163506/http://web.uvic.ca/~reimlab/noctdibrbear.pdf |archive-date=2017-08-12 |url-status=live }}</ref> Other species may be [[nocturnal]], active at night, though female sloth bears with cubs may feed more at daytime to avoid competition from conspecifics and nocturnal predators.<ref>{{Harvnb|Ward|Kynaston|1995|p=99}}</ref> Bears are overwhelmingly solitary and are considered to be the most asocial of all the Carnivora. The only times bears are encountered in groups are mothers with young or occasional seasonal bounties of rich food (such as salmon runs).<ref>{{cite book|author=Sandell, M. |year=1989|chapter=The mating tactics and spacing patterns of solitary carnivores|title=Carnivore behavior, ecology, and evolution |pages= 164–182|publisher= Springer |isbn=978-1-4613-0855-3|doi=10.1007/978-1-4613-0855-3_7}}</ref><ref name="Stonorov"/> Fights between males can occur and older individuals may have extensive [[scar]]ring, which suggests that maintaining [[Dominance (ethology)|dominance]] can be intense.<ref>{{Harvnb|Ward|Kynaston|1995|p=130}}</ref> With their acute sense of smell, bears can locate carcasses from several kilometres away. They use [[olfaction]] to locate other foods, encounter mates, avoid rivals and recognize their cubs.<ref name="Marshall Cavendish"/>

===Feeding===
[[File:Giant Panda Tai Shan.JPG|thumb|left|[[Giant panda]] feeding on [[bamboo]] at [[Smithsonian National Zoological Park]], [[Washington, D. C.]] This species is almost entirely [[herbivorous]].]]

Most bears are opportunistic [[omnivore]]s and consume more plant than animal matter, and appear to have evolved from an ancestor which was a low-protein macronutrient omnivore.<ref>{{cite journal | doi=10.1038/s41598-022-19742-z | title=Ursids evolved early and continuously to be low-protein macronutrient omnivores | year=2022 | last1=Robbins | first1=Charles T. | last2=Christian | first2=Amelia L. | last3=Vineyard | first3=Travis G. | last4=Thompson | first4=Debbie | last5=Knott | first5=Katrina K. | last6=Tollefson | first6=Troy N. | last7=Fidgett | first7=Andrea L. | last8=Wickersham | first8=Tryon A. | journal=Scientific Reports | volume=12 | issue=1 | page=15251 | pmid=36085304 | pmc=9463165 | bibcode=2022NatSR..1215251R }}</ref> They eat anything from leaves, roots, and [[berries]] to [[insect]]s, [[carrion]], fresh meat, and fish, and have digestive systems and teeth adapted to such a diet.<ref name="ServheenForeword"/> At the extremes are the almost entirely herbivorous giant panda and the mostly carnivorous polar bear. However, all bears feed on any food source that becomes seasonally available.<ref name="Ward83">{{Harvnb|Ward|Kynaston|1995|p=83}}</ref> For example, Asiatic black bears in [[Taiwan]] consume large numbers of [[acorn]]s when these are most common, and switch to [[ungulate]]s at other times of the year.<ref name="asiablackdiet">{{cite journal |last=Hwang |first=Mei-Hsiu |year=2002 |title=Diets of Asiatic black bears in Taiwan, with Methodological and Geographical Comparisons |url=http://www.bearbiology.com/fileadmin/tpl/Downloads/URSUS/Vol_13/Hwang_13.pdf |journal=Ursus |volume=13 |pages=111–125 |access-date=2012-12-22 |archive-url=https://web.archive.org/web/20130723060824/http://www.bearbiology.com/fileadmin/tpl/Downloads/URSUS/Vol_13/Hwang_13.pdf |archive-date=2013-07-23 |url-status=live }}</ref>

When foraging for plants, bears choose to eat them at the stage when they are at their most nutritious and digestible, typically avoiding older [[grass]]es, [[sedge]]s and leaves.<ref name="nps">{{cite web |title=Food Habits of Grizzly Bears and Black Bears in the Yellowstone Ecosystem |url=https://www.nps.gov/yell/learn/nature/bearfoods.htm |publisher=National Park Service |access-date=18 January 2017 |archive-url=https://web.archive.org/web/20170128071843/https://www.nps.gov/yell/learn/nature/bearfoods.htm |archive-date=2017-01-28 |url-status=live }}</ref><ref name="Ward83"/> Hence, in more northern temperate areas, browsing and grazing is more common early in spring and later becomes more restricted.<ref name="Mattson"/> Knowing when plants are ripe for eating is a learned behavior.<ref name="Ward83"/> Berries may be foraged in bushes or at the tops of trees, and bears try to maximize the number of berries consumed versus foliage.<ref name="Mattson"/> In autumn, some bear species forage large amounts of naturally [[fermentation|fermented]] fruits, which affects their behavior.<ref name="Rue1981">{{cite book |author=Rue, Leonard Lee |title=Furbearing Animals of North America |url=https://archive.org/details/furbearinganimal0000ruel |url-access=registration |year=1981 |publisher=Crown Publishers |isbn=978-0-517-53942-2 |page=[https://archive.org/details/furbearinganimal0000ruel/page/129 129]}}</ref> Smaller bears climb trees to obtain [[mast (botany)|mast]] (edible reproductive parts, such as acorns).<ref name="diet">{{cite journal |last=Mattson |first=David J. |journal=Ursus |year=1998 |title=Diet and Morphology of Extant and Recently Extinct Northern Bears |volume=10 |pages=479–496 | jstor=3873160}}</ref> Such masts can be very important to the diets of these species, and mast failures may result in long-range movements by bears looking for alternative food sources.<ref>{{cite journal |last1=Ryan |first1=Christopher |year=2007 |title=Influence of mast production on black bear non-hunting mortalities in West Virginia | journal=Ursus |volume=18 |issue=1 |pages=46–53 |doi=10.2192/1537-6176(2007)18[46:IOMPOB]2.0.CO;2 |last2=Pack |first2=James C. |last3=Igo |first3=William K. |last4=Billings |first4=Anthony|s2cid=59040812 }}</ref> Brown bears, with their powerful digging abilities, commonly eat roots.<ref name="Mattson"/> The panda's diet is over 99% bamboo,<ref>{{cite book |last1=Lumpkin |first1=Susan |last2=Seidensticker |first2=John |title=Giant Pandas |publisher=Collins |year=2007 |isbn=978-0-06-120578-1 |page=[https://archive.org/details/giantpandas0000seid/page/63 63] |url=https://archive.org/details/giantpandas0000seid/page/63 }}</ref> of 30 different species. Its strong jaws are adapted for crushing the tough stems of these plants, though they prefer to eat the more nutritious leaves.<ref>{{Harvnb|Ward|Kynaston|1995|pp=89–92}}</ref><ref>{{cite web |url=http://lrrd.cipav.org.co/lrrd4/2/dolberg.htm |title=Progress in the utilization of urea-ammonia treated crop residues: biological and socio-economic aspects of animal production and application of the technology on small farms |last=Dolberg |first=Frands |date=1 August 1992 |publisher=University of Arhus |access-date=10 August 2010 |archive-url=https://web.archive.org/web/20110707053325/http://lrrd.cipav.org.co/lrrd4/2/dolberg.htm |archive-date=2011-07-07 |url-status=live }}</ref> [[Bromeliad]]s can make up to 50% of the diet of the spectacled bear, which also has strong jaws to bite them open.<ref>{{Harvnb|Ward|Kynaston|1995|p=87}}</ref>
[[File:Polar bear (Ursus maritimus) with its prey.jpg|thumb|right|Polar bear feeding on a seal on an ice floe north of [[Svalbard]], Norway. It is the most carnivorous species.]]
The sloth bear is not as specialized as polar bears and the panda, has lost several front teeth usually seen in bears, and developed a long, suctioning tongue to feed on the [[ant]]s, [[termite]]s, and other burrowing insects. At certain times of the year, these insects can make up 90% of their diets.<ref>{{cite journal |last1=Joshi |first1=Anup |year=1997 |title=Seasonal and Habitat-Related Diets of Sloth Bears in Nepal |journal=Journal of Mammalogy |volume=1978 |issue=2 |pages=584–597 |doi=10.2307/1382910 |last2=Garshelis |first2=David L. |last3=Smith |first3=James L. D.|jstor=1382910 |doi-access=free }}</ref> Some individuals become addicted to sweets in garbage inside towns where tourism-related waste is generated throughout the year.<ref>{{Cite journal|last1=Prajapati|first1=Utkarsh|last2=Koli|first2=Vijay K.|last3=Sundar|first3=K.S. Gopi|date=2021|title=Vulnerable sloth bears are attracted to human food waste: a novel situation in Mount Abu town, India|journal=Oryx|volume=55|issue=5|pages=699–707|doi=10.1017/S0030605320000216|s2cid=233677898|doi-access=free}}</ref> Some species may raid the nests of [[wasp]]s and [[bee]]s for the [[honey]] and immature insects, in spite of stinging from the adults.<ref>{{cite web|title=What do bears like to eat in a beehive?|publisher=North American Bear Center|url=https://www.bear.org/website/bear-pages/black-bear/foraging-a-foods/206-what-do-bears-like-to-eat-in-a-beehive.html|access-date=5 April 2017|archive-url=https://web.archive.org/web/20170406110920/https://www.bear.org/website/bear-pages/black-bear/foraging-a-foods/206-what-do-bears-like-to-eat-in-a-beehive.html|archive-date=2017-04-06}}</ref> Sun bears use their long tongues to lick up both insects and honey.<ref>{{Harvnb|Ward|Kynaston|1995|p=89}}</ref> Fish are an important source of food for some species, and brown bears in particular gather in large numbers at [[salmon run]]s. Typically, a bear plunges into the water and seizes a fish with its jaws or front paws. The preferred parts to eat are the brain and eggs. Small burrowing mammals like [[rodent]]s may be dug out and eaten.<ref name="Ward193"/><ref name="Mattson"/>

The brown bear and both species of black bears sometimes take large ungulates, such as [[deer]] and [[bovid]]s, mostly the young and weak.<ref name="asiablackdiet"/><ref>{{cite journal |last1=Zager | first1=Peter |last2=Beecham |first2=John |year=2006 |title=The role of American black bears and brown bears as predators on ungulates in North America | journal=Ursus |volume=17 |issue=2 |pages=95–108 |doi=10.2192/1537-6176(2006)17[95:TROABB]2.0.CO;2| s2cid=85857613 }}</ref><ref name="Ward193">{{Harvnb|Ward|Kynaston|1995|pp=93–98}}</ref> These animals may be taken by a short rush and ambush, though hiding young may be sniffed out and pounced on.<ref name="Mattson">{{cite web|author=Mattson, David|publisher=Southwest Biological Science Center|title=Foraging Behavior of North American Bears |url=http://sbsc.wr.usgs.gov/cprs/research/projects/grizzly/pdf/FORAGINGBEHAVIOROFNORTHAMERICANBEARS.pdf |archive-url=https://web.archive.org/web/20070711074612/http://sbsc.wr.usgs.gov/cprs/research/projects/grizzly/pdf/FORAGINGBEHAVIOROFNORTHAMERICANBEARS.pdf|archive-date=11 July 2007}}</ref><ref>{{cite web|title=Animal Protein|publisher=North American bear Center|url=https://www.bear.org/website/bear-pages/black-bear/foraging-a-foods/84-animal-protein.html|access-date=22 March 2017|archive-url=https://web.archive.org/web/20170323142720/https://www.bear.org/website/bear-pages/black-bear/foraging-a-foods/84-animal-protein.html|archive-date=2017-03-23}}</ref> The polar bear mainly preys on seals, stalking them from the ice or breaking into their dens. They primarily eat the highly digestible blubber.<ref>{{Harvnb|Ward|Kynaston|1995|p=92}}</ref><ref name="Ward193"/> Large mammalian prey is typically killed with raw strength, including bites and paw swipes, and bears do not display the specialized killing methods of felids and canids.<ref name=Sacco2004>{{cite journal|last1=Sacco|first1=T|last2=Van Valkenburgh|first2=B|year=2004|title=Ecomorphological indicators of feeding behaviour in the bears (Carnivora: Ursidae)|journal=Journal of Zoology|volume=263|issue=1|pages=41–54|doi=10.1017/S0952836904004856}}</ref> Predatory behavior in bears is typically taught to the young by the mother.<ref name="Ward193"/>

Bears are prolific [[scavenger]]s and [[kleptoparasite]]s, stealing food [[Hoarding (animal behavior)|caches]] from rodents, and carcasses from other predators.<ref name="nps"/><ref>{{cite web |author=COSEWIC. Canadian Wildlife Service |title=Assessment and Update Status Report on the Grizzly Bear (''Ursus arctos'') |publisher=[[Environment Canada]] |year=2002 |url=http://dsp-psd.pwgsc.gc.ca/Collection/CW69-14-166-2002E.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://dsp-psd.pwgsc.gc.ca/Collection/CW69-14-166-2002E.pdf |archive-date=2022-10-09 |url-status=live |access-date=8 April 2007 }}</ref> For hibernating species, weight gain is important as it provides nourishment during winter dormancy. A brown bear can eat {{cvt|41|kg}} of food and gain {{cvt|2|–|3|kg}} of fat a day prior to entering its den.<ref>{{Harvnb|Ward|Kynaston|1995|p=104}}</ref>

===Communication===
[[File:Ursus thibetanus 01.JPG|thumb|left|[[Captive animal|Captive]] [[Asian black bear]]s during an aggressive encounter]]

Bears produce a number of vocal and non-vocal sounds. Tongue-clicking, grunting or chuffing many be made in cordial situations, such as between mothers and cubs or courting couples, while moaning, huffing, snorting or blowing air is made when an individual is stressed. Barking is produced during times of alarm, excitement or to give away the animal's position. Warning sounds include jaw-clicking and lip-popping, while teeth-chatters, [[Bellow (sound)|bellows]], [[growling|growl]]s, [[roar]]s and pulsing sounds are made in aggressive encounters. Cubs may squeal, bawl, bleat or scream when in distress and make motor-like humming when comfortable or nursing.<ref name="Ward117">{{Harvnb|Ward|Kynaston|1995|pp=117–121}}</ref><ref>{{cite book|author=Naughton, D.|year=2014|title=The Natural History of Canadian Mammals: Opossums and Carnivores|publisher=University of Toronto Press|pages=218–219, 236, 251–252|isbn=978-1-4426-4483-0}}</ref><ref>{{cite web |title=Vocalizations and Body Language |url=https://www.bear.org/website/bear-pages/black-bear/communication/29-vocalizations-a-body-language.html |publisher=North American Bear Center |access-date=7 January 2017 |archive-url=https://web.archive.org/web/20161223132123/https://www.bear.org/website/bear-pages/black-bear/communication/29-vocalizations-a-body-language.html |archive-date=2016-12-23  }}</ref><ref>{{cite book|author=Masterson, Linda|year=2016|title=Living With Bears Handbook: Expanded 2nd Edition|publisher=PixyJack Press|pages=215–16|isbn=978-1-936555-61-1}}</ref><ref name=Petersetal2007>{{cite journal |author=Peters, G. |author2=Owen, M. |author3=Rogers, L. |year=2007 |title=Humming in bears: a peculiar sustained mammalian vocalization |journal=Acta Theriologica |volume=52 |issue=4 |pages=379–389 |doi=10.1007/BF03194236 |s2cid=24886480 |url=https://www.researchgate.net/publication/227146528 |access-date=2017-09-08 |archive-url=https://web.archive.org/web/20140203154521/http://www.researchgate.net/publication/227146528_Humming_in_bears_a_peculiar_sustained_mammalian_vocalization/file/3deec5187efc99c3fc.pdf |archive-date=2014-02-03 |url-status=live }}</ref><ref>{{cite journal|author1=Laurie, A.|author2=Seidensticker, J.|year=1977|title=Behavioural ecology of the Sloth bear (''Melursus ursinus'')|journal=Journal of Zoology|volume=182|issue=2|pages=187–204|doi=10.1111/j.1469-7998.1977.tb04155.x|url=https://www.researchgate.net/publication/229976355|access-date=2017-03-26|archive-url=https://web.archive.org/web/20170327170117/https://www.researchgate.net/profile/John_Seidensticker/publication/229976355_Behavioural_ecology_of_the_Sloth_bear_Melursus_ursinus/links/53db8a9e0cf2a76fb667a2d1.pdf|archive-date=2017-03-27|url-status=live}}</ref>

[[File:Standing Sloth Bear.jpg|thumb|upright|[[Sloth bear]] rubbing against a tree at [[Nagarhole Tiger Reserve]], India]]

Bears sometimes communicate with visual displays such as [[bipedalism|standing upright]], which exaggerates the individual's size. The chest markings of some species may add to this intimidating display. Staring is an aggressive act and the facial markings of spectacled bears and giant pandas may help draw attention to the eyes during [[Agonistic behavior|agonistic]] encounters.<ref name="Ward124">{{Harvnb|Ward|Kynaston|1995|pp=124–125}}</ref> Individuals may approach each other by stiff-legged walking with the head lowered. Dominance between bears is asserted by making a frontal orientation, showing the [[canine teeth]], muzzle twisting and neck stretching.  A subordinate may respond with a lateral orientation, by turning away and dropping the head and by sitting or lying down.<ref name="Stonorov">{{cite journal |author1=Stonorov, D. |author2=Stokes, A. W. |year=1972 |title=Social behavior of the Alaska brown bear |volume=2 |pages=232–242 |url=http://www.bearbiology.com/fileadmin/tpl/Downloads/URSUS/Vol_2/Stonorov_Stokes.pdf |doi=10.2307/3872587 |journal= Bears: Their Biology and Management|access-date=2017-01-11 |archive-url=https://web.archive.org/web/20130722184419/http://www.bearbiology.com/fileadmin/tpl/Downloads/URSUS/Vol_2/Stonorov_Stokes.pdf |archive-date=2013-07-22 |url-status=live |jstor=3872587 }}</ref><ref>{{cite journal |author=Jordan, R. H. |s2cid=89660730 |year=1976 |title=Threat behavior of the black bear (''Ursus americanus'') |journal=Bears: Their Biology and Management |volume=40 |pages=57–63 |doi=10.2307/3872754|jstor=3872754 }}</ref>

Bears also communicate with their scent by [[Urination|urinating]] on<ref>{{Cite book |last1=Elbroch |first1=Mark |url=https://books.google.com/books?id=NGHgFgtJDQYC&dq=urine+rubbing&pg=PA194 |title=Field Guide to Animal Tracks and Scat of California |last2=Kresky |first2=Michael |last3=Evans |first3=Jonah Wy |date=2012-02-11 |publisher=University of California Press |isbn=978-0-520-25378-0 |language=en}}</ref> or [[Scent rubbing|rubbing]] against trees and other objects.<ref>{{cite journal|last1=Clapham|first1=M|last2=Nevin|first2=O. T.|last3=Ramsey|first3=A. D.|last4=Rossell|first4=F|year=2014|title=Scent-marking investment and motor patterns are affected by the age and sex of wild brown bears|journal=Animal Behaviour|volume=94|pages=107–116|doi=10.1016/j.anbehav.2014.05.017|s2cid=54371123}}</ref> This is usually accompanied by clawing and biting the object. Bark may be spread around to draw attention to the marking post.<ref>{{Harvnb|Ward|Kynaston|1995|p=122}}</ref> Pandas establish territories by marking objects with urine and a waxy substance from their anal glands.<ref>{{cite journal |author1=Nie, Y. |author2=Swaisgood, R. R. |author3=Zhang, Z. |author4=Hu, Y. |author5=Ma, Y. |author6=Wei, F. |year=2012 |title=Giant panda scent-marking strategies in the wild: role of season, sex and marking surface |journal=Animal Behaviour |volume=84 |issue=1 |pages=39–44 |doi=10.1016/j.anbehav.2012.03.026|s2cid=53256022 }}</ref> Polar bears leave behind their scent in their tracks which allow individuals to keep track of one another in the vast Arctic wilderness.<ref>{{cite journal |author1=Owen, M. A.|author2=Swaisgood, R. R. |author3=Slocomb, C. |author4=Amstrup, S. C. |author5=Durner, G. M. |author6=Simac, K. |author7=Pessier, A. P. |year=2014 |title=An experimental investigation of chemical communication in the polar bear |journal=Journal of Zoology |volume=295 |issue=1 |pages=36–43 |doi=10.1111/jzo.12181}}</ref>

===Reproduction and development{{anchor|Breeding}}===
[[File:Black Bears mating.jpg|thumb|left|American black bears mating at the [[North American Bear Center]]]]

The mating system of bears has variously been described as a form of [[Polygyny in animals|polygyny]], [[Promiscuity#Other animals|promiscuity]] and [[serial monogamy]].<ref>{{cite web |author1=Eide, S. |author2=Miller, S. |title=Brown Bear |publisher=Alaska Department of Fish and Game |url=https://www.adfg.alaska.gov/static/education/wns/brown_bear.pdf |access-date=14 January 2016 |archive-url=https://web.archive.org/web/20130303124834/http://www.adfg.alaska.gov/static/education/wns/brown_bear.pdf |archive-date=2013-03-03 |url-status=live }}</ref><ref name="Ward138">{{Harvnb|Ward|Kynaston|1995|pp=138–141}}</ref><ref name=mammalian>{{cite journal |author=Lariviere, S. |year=2001 |title=Ursus americanus |journal=Mammalian Species |issue=647 |pages=1–11 |url=http://www.science.smith.edu/msi/pdf/647_Ursus_americanus.pdf |doi=10.1644/1545-1410(2001)647<0001:ua>2.0.co;2 |s2cid=198968922  |archive-url=https://web.archive.org/web/20160316025524/http://www.science.smith.edu/msi/pdf/647_Ursus_americanus.pdf |archive-date=2016-03-16 }}</ref> During the breeding season, males take notice of females in their vicinity and females become more tolerant of males. A male bear may visit a female continuously over a period of several days or weeks, depending on the species, to test her reproductive state. During this time period, males try to prevent rivals from interacting with their mate. Courtship may be brief, although in some Asian species, courting pairs may engage in wrestling, hugging, mock fighting and vocalizing. [[Induced ovulation (animals)|Ovulation is induced by mating]], which can last up to 30 minutes depending on the species.<ref name="Ward138"/>

[[File:Cub polar bear is nursing 2.OGG|thumb|[[Polar bear]] mother nursing her cub]]
[[Gestation]] typically lasts six to nine months, including [[delayed implantation]], and litter size numbers up to four cubs.<ref name="Ward144">{{Harvnb|Ward|Kynaston|1995|pp=144–148}}</ref> Giant pandas may give birth to twins but they can only suckle one young and the other is left to die.<ref name="Panda Facts">{{cite web |url=http://www.pandasinternational.org/wptemp/education-2/panda-facts/ |title=Panda Facts |publisher=Pandas International |access-date=26 August 2015  |archive-url=https://web.archive.org/web/20150924063658/http://www.pandasinternational.org/wptemp/education-2/panda-facts/ |archive-date=24 September 2015 }}</ref> In northern living species, birth takes place during winter dormancy. Cubs are born blind and helpless with at most a thin layer of hair, relying on their mother for warmth. The milk of the female bear is rich in fat and antibodies and cubs may suckle for up to a year after they are born. By two to three months, cubs can follow their mother outside the den. They usually follow her on foot, but sloth bear cubs may ride on their mother's back.<ref name="Ward144"/><ref name=Walker>{{cite book |author=Nowak, R. M. |year=2005 |title=Walker's Carnivores of the World |publisher=Johns Hopkins University Press |page=[https://archive.org/details/walkerscarnivore0000nowa/page/114 114] |isbn=978-0-8018-8032-2 |url=https://archive.org/details/walkerscarnivore0000nowa/page/114 }}</ref> Male bears play no role in raising young. [[Infanticide (zoology)|Infanticide]], where an adult male kills the cubs of another, has been recorded in polar bears, brown bears and American black bears but not in other species.<ref>{{Harvnb|Ward|Kynaston|1995|p=132}}</ref> Males kill young to bring the female into [[estrus]].<ref name=Bellemain>{{cite journal|doi=10.1111/j.1439-0310.2006.01152.x|title=Mating Strategies in Relation to Sexually Selected Infanticide in a Non-Social Carnivore: The Brown Bear|url=http://bearproject.info/wp-content/uploads/2015/11/2006-A060-Bellemain-Mating-Strategies-in-relation-to-SSI.pdf|journal=Ethology|volume=112|issue=3|pages=238–246|year=2006|last1=Bellemain|first1=Eva|last2=Swenson|first2=Jon E.|last3=Taberlet|first3=Pierre|bibcode=2006Ethol.112..238B |access-date=2017-05-02|archive-url=https://web.archive.org/web/20161221015155/http://bearproject.info/wp-content/uploads/2015/11/2006-A060-Bellemain-Mating-Strategies-in-relation-to-SSI.pdf|archive-date=2016-12-21|url-status=live}}</ref> Cubs may flee and the mother defends them even at the cost of her life.<ref>{{cite journal |author1=Bellemain, E. |author2=Zedrosser, A. |author3=Manel, S. |author4=Waits, L. P. |author5=Taberlet, P. |author6=Swenson, J. E. |year=2005 |pmid=16543170 |pmc=1560043 |title=The dilemma of female mate selection in the brown bear, a species with sexually selected infanticide |journal=Proceedings of the Royal Society of London B: Biological Sciences |volume=273 |issue=1584 |pages=283–291 |doi=10.1098/rspb.2005.3331}}</ref><ref>{{cite journal |author1=Swenson, J. E. |author2=Dahle, B. |author3=Sandegren, F. |year=2001 |title=Intraspecific predation in Scandinavian brown bears older than cubs-of-the-year |journal=Ursus |volume=12 |pages=81–91 |jstor=3873233 |url=https://www.researchgate.net/publication/237374836 |access-date=2017-01-14 |archive-url=https://web.archive.org/web/20171116185901/https://www.researchgate.net/publication/237374836_Intraspecific_predation_in_Scandinavian_brown_bears_older_than_cubs-of-year |archive-date=2017-11-16 |url-status=live }}</ref><ref name="Mörner">{{cite journal |author1=Mörner, T. |author2=Eriksson, H. |author3=Bröjer, C. |author4=Nilsson, K. |author5=Uhlhorn, H. |author6=Ågren, E. |author7=af Segerstad, C.H. |author8=Jansson, D.S. |author9=Gavier-Widén, D. |year=2005 |title=Diseases and mortality in free-ranging brown bear (''Ursus arctos''), gray wolf (''Canis lupus''), and wolverine (''Gulo gulo'') in Sweden |journal=Journal of Wildlife Diseases |volume=41 |issue=2 |pages=298–303 |pmid=16107663 |doi=10.7589/0090-3558-41.2.298|doi-access=free }}</ref>

In some species, offspring may become independent around the next spring, though some may stay until the female successfully mates again. Bears reach [[sexual maturity]] shortly after they disperse; at around three to six years depending on the species. Male Alaskan brown bears and polar bears may continue to grow until they are 11 years old.<ref name="Ward144"/> Lifespan may also vary between species. The brown bear can live an average of 25 years.<ref>{{cite web|title=Grizzly Bear|date=10 September 2010 |publisher=National Geographic.com|access-date=29 April 2017|url=http://www.nationalgeographic.com/animals/mammals/g/grizzly-bear/|archive-url=https://web.archive.org/web/20170421214527/http://www.nationalgeographic.com/animals/mammals/g/grizzly-bear/|archive-date=2017-04-21|url-status=dead}}</ref>

===Hibernation{{anchor|Winter_dormancy}}===
{{main|Hibernation}}

Bears of northern regions, including the [[American black bear#Hibernation|American black bear]] and the [[Grizzly bear#Hibernation|grizzly bear]], hibernate in the winter.<ref name=Science2011>{{cite journal | author=Gerhard Heldmeier | year=2011 | title=Life on low flame in hibernation | journal=Science | volume=331 | issue=6019 | pages=866–867 | doi=10.1126/science.1203192 | pmid=21330523| bibcode=2011Sci...331..866H | s2cid=31514297 }}</ref><ref name=Shimozuru2013>{{cite journal |author=Shimozuru, M. |year=2013 |title=Pregnancy during hibernation in Japanese black bears: effects on body temperature and blood biochemical profiles |journal=Journal of Mammalogy |volume=94 |issue=3 |pages=618–627 |doi=10.1644/12-MAMM-A-246.1 |s2cid=86174817 |display-authors=etal|doi-access=free }}</ref> During hibernation, the bear's metabolism slows down, its body temperature decreases slightly, and its heart rate slows from a normal value of 55 to just 9 beats per minute.<ref name=Toien2011>{{cite journal |author=Tøien, Ø. |s2cid=20829847 |year=2011 |title=Hibernation in Black Bears: Independence of Metabolic Suppression from Body Temperature |journal=Science |volume=331 |issue=6019 |pages=906–909 |doi=10.1126/science.1199435 |pmid=21330544 |display-authors=etal|bibcode=2011Sci...331..906T }}</ref> In order for their heart rate to slow down to this level during hibernation, a protein found in striated muscle, like the heart, called myosin must enter a super-relaxed state. In the super-relaxed state, the consumption of ATP is kept very low, allowing the bear to make it through the winter without losing all of its energy due to the basic functions such as pumping blood through the body.<ref>{{Cite journal |last1=Van der Pijl |first1=Robbert J. |last2=Ma |first2=Weikang |last3=Lewis |first3=Christopher T. A. |last4=Haar |first4=Line |last5=Buhl |first5=Amalie |last6=Farman |first6=Gerrie P. |last7=Rhodehamel |first7=Marcus |last8=Jani |first8=Vivek P. |last9=Nelson |first9=O Lynne |last10=Zhang |first10=Chengxin |last11=Granzier |first11=Henk |last12=Ochala |first12=Julien |date=2025-02-01 |title=Increased cardiac myosin super-relaxation as an energy saving mechanism in hibernating grizzly bears |url=https://www.sciencedirect.com/science/article/pii/S2212877824002151 |journal=Molecular Metabolism |volume=92 |pages=102084 |doi=10.1016/j.molmet.2024.102084 |pmid=39694092 |issn=2212-8778|pmc=11732570 }}</ref> Bears normally do not wake during their hibernation, and can go the entire period without eating, drinking, urinating, or defecating.<ref name="Marshall Cavendish"/> A [[fecal plug]] is formed in the colon, and is expelled when the bear wakes in the spring.<ref>{{cite web|last1=Biel|first1=M|last2=Gunther|first2=K|title=Denning and Hibernation Behavior|url=https://www.nps.gov/yell/learn/nature/denning.htm|website=Yellowstone National Park|publisher=National Park Service|access-date=18 November 2016|archive-url=https://web.archive.org/web/20161118101716/https://www.nps.gov/yell/learn/nature/denning.htm|archive-date=2016-11-18|url-status=live}}</ref> If they have stored enough body fat, their muscles remain in good condition, and their protein maintenance requirements are met from recycling waste [[urea]].<ref name="Marshall Cavendish"/> While larger bears have a larger supply of body fat to keep them alive through hibernation, researchers found that smaller bears were able to hibernate longer than their larger counterparts due to them being able to sustain a lower body temperature, which translates to less energy being spent on keeping their bodies warm.<ref>{{Cite journal |last1=Evans |first1=Alina L. |last2=Fuchs |first2=Boris |last3=Singh |first3=Navinder J. |last4=Thiel |first4=Alexandra |last5=Giroud |first5=Sylvain |last6=Blanc |first6=Stephane |last7=Laske |first7=Timothy G. |last8=Frobert |first8=Ole |last9=Friebe |first9=Andrea |last10=Swenson |first10=Jon E. |last11=Arnemo |first11=Jon M. |date=2023-08-17 |title=Body mass is associated with hibernation length, body temperature, and heart rate in free-ranging brown bears |journal=Frontiers in Zoology |volume=20 |issue=1 |pages=27 |doi=10.1186/s12983-023-00501-3 |doi-access=free |issn=1742-9994 |pmc=10433566 |pmid=37587452}}</ref> Female bears give birth during the hibernation period, and are roused when doing so.<ref name="Shimozuru2013"/>

===Mortality===
[[File:Björnjakt i Dalarna - Nordiska Museet - NMA.0052736.jpg|thumb|right|Hunters with shot bear, Sweden, early 20th century. This photograph is in the [[Nordic Museum]].]]

Bears do not have many predators. The most important are humans, and as they started cultivating crops, they increasingly came in conflict with the bears that raided them. Since the invention of firearms, people have been able to kill bears with greater ease.<ref>{{cite journal |author=McTaggart Cowan, I. |year=1972 |title=The Status and Conservation of Bears (Ursidae) of the World: 1970 |journal=Bears: Their Biology and Management |volume=2 |pages=343–367 |doi=10.2307/3872596 |citeseerx=10.1.1.483.1402 |jstor=3872596 }}</ref> [[Felid]]s like the [[tiger]] may also prey on bears,<ref name="Seryodkin_PhD">{{cite book |url=http://uml.wl.dvgu.ru/rscv.php?id=74 |title=The ecology, behavior, management and conservation status of brown bears in Sikhote-Alin |language=ru |author=Seryodkin, Ivan |year=2006 |publisher=Far Eastern National University, Vladivostok, Russia |pages=1–252  |archive-url=https://web.archive.org/web/20131224090426/http://uml.wl.dvgu.ru/rscv.php?id=74 |archive-date=2013-12-24 }}</ref><ref name="Denning">{{cite journal |url=http://www.wcsrussia.org/DesktopModules/Bring2mind/DMX/Download.aspx?EntryId=3313&PortalId=32&DownloadMethod=attachment |author=Seryodkin |year=2003 |title=Denning ecology of brown bears and Asiatic black bears in the Russian Far East |journal=Ursus |volume=14 |issue=2 |page=159 |display-authors=etal |access-date=2014-10-05 |archive-url=https://web.archive.org/web/20110817151324/http://www.wcsrussia.org/DesktopModules/Bring2mind/DMX/Download.aspx?EntryId=3313&PortalId=32&DownloadMethod=attachment |archive-date=2011-08-17 |url-status=live }}</ref> particularly cubs, which may also be threatened by canids.<ref name=Servheen1999/><ref name=mammalian/>

Bears are parasitized by eighty species of parasites, including single-celled protozoans and gastro-intestinal worms, and nematodes and flukes in their heart, liver, lungs and bloodstream. Externally, they have ticks, fleas and lice. A study of American black bears found seventeen species of endoparasite including the protozoan ''[[Sarcocystis]]'', the parasitic worm ''[[Diphyllobothrium mansonoides]]'', and the nematodes ''[[Dirofilaria immitis]]'', ''[[Capillaria aerophila]]'', ''[[Physaloptera]]'' sp., ''[[Strongyloides]]'' sp. and others. Of these, ''D. mansonoides'' and adult ''C. aerophila'' were causing pathological symptoms.<ref name=Crum>{{cite journal |author1=Crum, James M. |author2=Nettles, Victor F. |author3=Davidson, William R. |year=1978 |title=Studies on endoparasites of the black bear (''Ursus americanus'') in the southeastern United States |journal=Journal of Wildlife Diseases |volume=14 |issue=2 |pages=178–186 |doi=10.7589/0090-3558-14.2.178 |pmid=418189 |doi-access=free }}</ref> By contrast, polar bears have few parasites; many parasitic species need a secondary, usually terrestrial, host, and the polar bear's life style is such that few alternative hosts exist in their environment. The protozoan ''[[Toxoplasma gondii]]'' has been found in polar bears, and the nematode ''[[Trichinella nativa]]'' can cause a serious infection and decline in older polar bears.<ref name=Derocher>{{cite book |author=Derocher, Andrew E. |title=Polar Bears: A Complete Guide to Their Biology and Behavior |url=https://books.google.com/books?id=aouJPNt1P4gC&pg=PT212 |year=2012 |publisher=JHU Press |isbn=978-1-4214-0305-2 |page=212}}</ref> Bears in North America are sometimes infected by a ''[[Morbillivirus]]'' similar to the [[Canine distemper|canine distemper virus]].<ref>{{cite book |title=Emergence and Control of Zoonotic Ortho- and Paramyxovirus Diseases | year=2001 |url=https://books.google.com/books?id=U1lIR14667cC&pg=PA167 |publisher=John Libbey Eurotext |isbn=978-2-7420-0392-1 |page=167}}</ref> They are susceptible to [[infectious canine hepatitis]] (CAV-1), with free-living black bears dying rapidly of encephalitis and hepatitis.<ref name=Williams>{{cite book |author1=Williams, Elizabeth S. |author2=Barker, Ian K. |title=Infectious Diseases of Wild Mammals |url=https://books.google.com/books?id=HJDsAU-NWiYC&pg=PA203 |year=2008 |publisher=John Wiley & Sons |isbn=978-0-470-34481-1 |page=203}}</ref>