Editing Polar bear (section)

===Captivity===
[[File:Polar Bear at DZ.jpg|thumb|right|Visitors observing polar bears underneath a plexiglass tunnel at the [[Detroit Zoo]]]]
The polar bear was for long a particularly sought-after species for exotic animal collectors, since it was relatively rare and remote living and had a reputation as a ferocious beast.{{sfn|Engelhard|2017|pp=96}} It is one of the few marine mammals that will reproduce well in captivity.<ref name=Perrin>{{cite book|editor-first1=William F.|editor-last1=Perrin|editor-first2=Bernd |editor-last2= Wursig|editor-first3=J. G. M. 'Hans' |editor-last3=Thewissen|title=Encyclopedia of Marine Mammals|year=2009|publisher=Academic Press|isbn=978-0-08-091993-5|last1=Robeck|first1=T. R.|last2=O'Brien|first2=J. K.|last3=Obell|first3=D. K. |contribution=Captive Breeding|pages=178}}</ref> They were originally kept only by royals and elites. The [[Tower of London]] got a polar bear as early as 1252 under [[Henry III of England|King Henry III]]. In 1609, [[James VI and I]] of Scotland, England and Ireland was given two polar bear cubs by the sailor [[Jonas Poole]], who got them during a trip to [[Svalbard]].{{sfn|Fee|2019|pp=32, 103, 105}} At the end of the 17th century, [[Frederick I of Prussia]] housed polar bears in [[menagerie]]s with other wild animals. He had their claws and canines removed to allow them to perform mock fights safely. Around 1726, [[Catherine I of Russia]] gifted two polar bears to [[Augustus II the Strong]] of Poland, who desired them for his animal collection.{{sfn|Engelhard|2017|pp=95}} Later, polar bears were displayed to the public in [[zoo]]s and [[circus]]es.{{sfn|Fee|2019|pp=103, 108}} In early 19th century, the species was exhibited at the [[Exeter Exchange]] in London, as well as menageries in Vienna and Paris. The first zoo in North America to exhibit a polar bear was the [[Philadelphia Zoo]] in 1859.{{sfn|Engelhard|2017|pp=xii, 96–97}}

Polar bear exhibits were innovated by [[Carl Hagenbeck]], who replaced cages and pits with settings that mimicked the animal's natural environment.  In 1907, he revealed a complex [[panoramic]] structure at the [[Tierpark Hagenbeck]] Zoo in Hamburg consisting of exhibits made of artificial snow and ice separated by moats. Different polar animals were displayed on each platform, giving the illusion of them living together. Starting in 1975, [[Hellabrunn Zoo]] in Munich housed its polar bears in an exhibit which consisted of a glass barrier, a house, concrete platforms mimicking ice floes and a large pool. Inside the house were maternity dens, and rooms for the staff to prepare and store the food. The exhibit was connected to an outdoor yard for extra room. Similar naturalistic and "immersive" exhibits were opened in the early 21st century, such as the "Arctic Ring of Life" at the [[Detroit Zoo]] and Ontario's [[Cochrane, Ontario|Cochrane]] Polar Bear Habitat.{{sfn|Engelhard|2017|pp=7, 101, 105–106}}{{sfn|Fee|2019|p=118}} Many zoos in Europe and North America have stopped keeping polar bears because of the size and costs of their complex exhibits.{{sfn|Fee|2019|pp=120–121}} In North America, the population of polar bears in zoos reached its zenith in 1975 with 229 animals and declined in the 21st century.<ref>{{cite journal|last1=Curry|first1=E|last2=Safay|first2=S|last3=Meyerson|first3=R|last4=Roth|first4=T. L.|year=2015|title=Reproductive trends of captive polar bears in North American zoos: a historical analysis|journal=Journal of Zoo and Aquarium Research|volume=3|issue=3|pages=99–106|doi=10.19227/jzar.v3i3.133}}</ref>
[[File:Repetitie Nationaal Songfestival in Carré, Sylvia de Leur dresseert beren, Bestanddeelnr 926-2489.jpg|thumb|left|Performing polar bear at the 1973 ''[[Nationaal Songfestival]]'' in the Netherlands]]
Polar bears have been trained to perform in circuses. Bears in general, being large, powerful, easy to train and human-like in form, were widespread in circuses, and the white coat of polar bears made them particularly attractive. Circuses helped change the polar bear's image from a fearsome monster to something more comical. Performing polar bears were used in 1888 by [[Circus Krone]] in Germany and later in 1904 by the [[Frank C. Bostock|Bostock and Wombwell Menagerie]] in England. Circus director Wilhelm Hagenbeck trained up to 75 polar bears to slide into a large tank through a chute. He began performing with them in 1908 and they had a particularly well-received show at the [[Hippodrome, London|Hippodrome in London]]. Other circus tricks performed by polar bears involved tightropes, balls, roller skates and motorcycles. One of the most famous polar bear trainers in the second half of the twentieth century was the East German Ursula Böttcher, whose small stature contrasted with that of the large bears. Starting in the late 20th century, most polar bear acts were retired and the use of these bears for the circus is now prohibited in the US.{{sfn|Engelhard|2017|pp=109–111, 116–119}}

Several captive polar bears gained celebrity status in the late 20th and early 21st century, notably [[Knut (polar bear)|Knut]] of the [[Berlin Zoological Garden]], who was rejected by his mother and had to be hand-reared by zookeepers. Another bear, [[Binky (polar bear)|Binky]] of the [[Alaska Zoo]] in Anchorage, became famous for attacking two visitors who got too close.{{sfn|Engelhard|2017|pp=21–24, 105}}{{sfn|Fee|2019|pp=123–124, 145}} Captive polar bears may pace back and forth, a [[Stereotypy (non-human)|stereotypical behaviour]]. In one study, they were recorded to have spent 14 percent of their days pacing.<ref>{{cite journal|last1=Shepherdson|first1=D.|last2=Lewis|first2=K. D.|last3=Carlstead|first3=K.|last4=Bauman|first4=J.|last5=Perrin|first5=N.|year=2013|title=Individual and environmental factors associated with stereotypic behavior and fecal glucocorticoid metabolite levels in zoo housed polar bears|journal=Applied Animal Behaviour Science|volume=147|issue=3–4|pages=268–277|doi=10.1016/j.applanim.2013.01.001}}</ref> [[Gus (bear)|Gus]] of the [[Central Park Zoo]] was prescribed [[Prozac]] by a therapist for constantly swimming in his pool.{{sfn|Engelhard|2017|p=24}} To reduce stereotypical behaviours, zookeepers provide the bears with enrichment items to trigger their play behaviour.<ref>{{cite journal|last1=Canino|first1=W.|last2=Powell|first2=D.|year=2010|title=Formal behavioral evaluation of enrichment programs on a zookeeper's schedule: a case study with a polar bear (''Ursus maritimus'') at the Bronx Zoo|journal=Zoo Biology|volume=29|issue=4|pages=503–508|doi=10.1002/zoo.20247|pmid=19373879}}</ref> In sufficiently warm conditions, [[algae]] concentrated in the medulla of their fur's guard hairs may cause zoo polar bears to appear green.<ref>{{cite journal|last1=Lewin|first1=R. A.|last2=Farnsworth|first2=P. A.|last3=Yamanaka|first3=G.|year=1981|title=The algae of green polar bears|journal=Phycologia|volume=20|issue=3 |pages=303–314|doi=10.2216/i0031-8884-20-3-303.1|bibcode=1981Phyco..20..303L }}</ref>