NorthPoleisthenorthernendoftheEarthspinaxis,thatisthepointof90°northlatitude.ArcticneartheNorthPoleislatitude66°34''areawithintheArcticCircle.ThefrozenArcticOceanisavastocean,surroundedbynumerousislandsandcoastalareasofnorthernNorthAmericaandAsia.ColdwatersoftheicebergfromtheArcticOceanflowscarryingtheAtlanticandPacific.Arcticcoldclimatethroughouttheyear.Winter,thesunisalwaysbelowthehorizon,theseaicecompletelyfrozen.Summer,thetemperaturerosetoabovefreezing,meltingtheedgeoftheArcticOcean,thesunforweeksarehanginginthesky.ArcticOceanarerichinfishandplankton,Thissummerhere,millionsofseabirdsnestingprovidesarichsourceoffood,andalsotheseals,whalesandothermarineanimals.MostareasaroundtheArcticOceanareflat,notrees.Winter,frozenearth,thegroundcoveredwiththicksnow.Summersnowmelt,thawthesurfacesoil,plantsgrowandblossom,asthereindeerandmuskoxenandotheranimalswithfood.Meanwhile,wolvesandpolarbearsandotherpredatorsalsodependonotheranimalstosurvivepredation.Arcticistheworld''smostsparselypopulatedareas.Sincecenturies,theInuitformerlyEskimosoundreproductionfromgenerationtogenerationhere.Recently,thediscoveryofoilhere,somanypeoplecametoworkherefromthesouth.ThemostrepresentativeandsymbolicanimalistheArcticpolarbears.Asthenamesuggests,polarbearsliveintheArctic.TheirhomeintheArcticiceandthesurroundingislands,aswellastheadjacentmainlandnearthecoast,wasthecircumpolardistributionofbasic.Theygenerallywillnotgodeepintomorenorthernareas,wheretheiceistoothick,andeventheirmainprey-sealscannotbreaktheiceout,nofood,polarbearswillnaturallynottaketherisk.Polarbearslivingtherewereclassifiedintosixspecies:RussiaWrangelIsland-AlaskaWesternpopulations;populationinnorthernAlaska;theCanadianArcticarchipelagopopulation;Greenlandpopulation;Norway,Svalbard-俄罗斯法兰兹JosephIslandpopulationandtocentralpopulationsinnorthernSiberia.Polarbearinthebearfamilyanimalfamilyaregenuinecarnivores,theyfeedseals,especiallyringedseals,willalsopreybeardedseal,harpseal,crownseals.Inaddition,theyalsocapturethewalrus,belugawhales,seabirds,fish,smallmammals,sometimescleaningthecarrion.,Andotherbearspecieshavedifferent,theyarenoteatingthefoodwillnothideaftertheeat,etc.Thisisonegreatconveniencetootheranimals,suchasArcticfoxlazyorsimilar,evenafterthefatfromtimetotimetoenjoycompletetowalkaway,knowthatforthem,high-caloriefatismoreimportantthanthemeat,Becausetheyneedtomaintainawarmlayeroffatused,alsoneedtostoreenergywhenfoodshortages.Polarbearsarenotvegetariansdonotstickalittle,occasionallyinthesummertheyeatberriesorplantroots,althoughtheyarenothighintermsofnutritionalvalue.Polarbearsareexcellentswimmers,sothatoncepeoplebelievethatmarineanimals,itisnotonlytheLatinnameU.maritimusmeans"sea"Bear.Polarbearsintheirlivesmostofthetime66.6%wereinthe"static"state,suchassleeping,lyingdownresting,orwaitingforprey.Theremainingapproximately29.1%ofthetimewalkingorswimmingintheland,1.2%ofthetimeintheattackprey,whatisleftistobasicallyenjoydelicious.Therearetwokindspolarbearhuntingmode,themostcommonisthe"passive"method.Theywilladvancetofindtheiceseal''sbreathingholeAndhighlyendurancewaitingseveralhoursinthenext.Waituntilthesealsappear,theywilllaunchasurpriseattack,withsharpclawshooktodragthesealupfromthebreathinghole.Ifthesealsonshore,theywouldhideinplaceswheresealseyecannotsee,andthencrepttocomecrawlingtolaunchonslaught.Anothermodelistosneakintotheicedirectlyundersealuntilclosetotheshorebeforetheattack,sotheadvantageisadirectescaperoutecutofftheseals.Satiate,thepolarbearswillcarefullycleanupthehair,thefoodresidueofbloodarecleaned.北极是指地球自转轴的北端，也就是北纬90°的那一点。北极地区是指北极附近北纬66°34′北极圈以内的地区。北冰洋是一片浩瀚的冰封海洋，周围是众多的岛屿以及北美洲和亚洲北部的沿海地区。冰冷的海水携带着冰山从北冰洋流入大西洋和太平洋。北极地区的气候终年寒冷。冬季，太阳始终在地平线以下，大海完全封冻结冰。夏季，气温上升到冰点以上，北冰洋的边缘地带融化，太阳连续几个星期都挂在天空。北冰洋中有丰富的鱼类和浮游生物，这为夏季在这里筑巢的数百万只海鸟提供了丰富的食物来源，同时，也是海豹、鲸和其他海洋动物的食物。北冰洋周围的大部分地区都比较平坦，没有树木生长。冬季大地封冻，地面上覆盖着厚厚的积雪。夏季积雪融化，表层土解冻，植物生长开花，为驯鹿和麝牛等动物提供了食物。同时，狼和北极熊等食肉动物也依靠捕食其他动物得以存活。北极地区是世界上人口最稀少的地区之一。千百年以来，因纽特人是处于“静止”状态，例如睡觉、躺着休息，或者是守候猎物。剩下约有29.1％的时间是在陆地行走或游水，1.2％的时间在袭击猎物，最后剩下的时间基本是在享受美味。北极熊一般有两种捕猎模式，最常用的是“守株待兔”法。它们会事先在冰面上找到海豹的呼吸孔，然后极富耐力地在旁边等候几个小时。等到海豹一露头，它们就会发动突然袭击，并用尖利的爪钩将海豹从呼吸孔中拖上来。如果海豹在岸上，它们也会躲在海豹视线看不到的地方，然后蹑手蹑脚地爬将过来发起猛攻。另外一种模式就是直接潜入冰面下，直到靠近岸上的海豹才发动进攻，这样的优点是直接截断了海豹的退路。吃饱喝足后，北极熊会细心清理毛发，把食物的残渣血迹都清除干净。
赵颖鸿2019-11-05 22:06:44