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SevenWorld,OnePlanetS01E07七个世界一个星球第七集Africa.非洲NocontinentonEarthtodayhassuchspectacularwildlife.这里拥有世界上最为雄浑壮丽的野生动物奇观。Atitsheartliesavasttropicalrainforest.大陆中心是郁郁葱葱的广阔热带雨林。Overamillionsquaremilesofwilderness,muchofitstillunexploredevennow.一片占地200多万平方公里的荒野，大部分是迄今都无人涉足的原始森林。Therearemorespeciesofanimalsandplantsinthesejunglesthananywhereelseonthecontinent.这里野生动植物多样，种类之多超过非洲大陆的其它任何地方。Buteveninthislandofplentywildlifenowfacesmajorchallenges.但即使是在这片富饶之地，野生动物们也面临着许多严峻挑战。TheforestsoftheIvoryCoastcontainover1,500speciesofplant,butsomeareverydifficulttogetatevenforoneofthemostintelligentofanimals.非洲科特迪瓦的森林资源丰富，共有1500多种植物，但有些很难获得，就连一些最聪明伶俐的动物也只能望洋兴叹。Chimpanzees.黑猩猩。Theeldersinthisgroupknowwheretofindthemostnutritiousfoodandhowtoextractit.这个族群的长者知道从哪里能找到最有营养的食物以及如何提取其中的养分。Butiftheyaretosurvivetoadulthood,theyoungstersmustlearntheseskillsfromtheirparents.年轻幼崽要想长大成年，必须跟随父母学习这些生存技能。Thisyoungfemaleisfiveyearsoldoldenoughtobegivenanimportantlesson.这只年轻雌性黑猩猩今年5岁，这个年纪可以学习一门重要的课程了。Andthisisherteacher.这是负责传授知识的老师。Hermother.也是它的妈妈。Thelessonishowtocrackanut.课程内容是学习如何打开坚果。Usingtoolslikethisissocomplexthatithasonlybeenmasteredbyahandfulofchimpanzeecommunities.熟练使用工具是一项复杂的技能，所以目前只有少数黑猩猩群体能够掌握。Thisisaskillthathasbeenpractisedbychimpsforseveralthousandyears.这是黑猩猩历经数千年通过不断实践获得的非凡本领。Timetotryforherself.可以自己试一下了。Sheneedstofindabettertool.它需要找到一个更好的工具。Smallrocksjustdon'thavetheclout.小石块的撞击力不够大Andlargeronesaretoocumbersome.大石头又显得过于笨重。Woodisbothlightandstrongbutnotstrongenough.木头看似既轻便又结实但用在这里还不够。Backtoteacher.它返回继续观摩学习。Itmaytakeayoungchimpuptoadecadetoperfecttheskillsitneedsfornut-cracking.年轻黑猩猩可能需要将近10年才能熟练掌握敲碎坚果的技能。Butshe'salreadymasteredonething.但它现在已经掌握了一项本领。Whenherfingerscan'treachthenutinsideshestripsdownabranchtosizeandmakesherselfaspoon.当手指够不到果仁时，它会折下一根树枝，调整到合适大小当成勺子用。She'lllearntousemanytoolsinherlifeandeventuallyshe'llsharethisknowledgewithyoungstersofherown,enablingthemtoharvesttherichesoftheirrainforesthome.它一生中要学习使用许多工具，最终它会把这些知识传授给自己的幼崽，使它们能够在广阔的雨林家园里尽情享用各种各样的食物资源。Thesheerabundanceoflifeintherainforestsisrivalledbythatontheeasternsideofthecontinent.热带雨林中纷繁多样的动植物令人眼花缭乱，而东非的物种之多毫不逊色。TheGreatRiftValleyrunsfor4,000milesdownthelengthofAfrica.大裂谷是纵贯东非南北的地理奇观总长近6500公里。Itdevelopedsome30millionyearsago,whenagiantplumeofmoltenrockpushingupfromthedepthscrackedtheEarth'scrustapart.它形成于大约3000万年前，由于地壳板块运动，一股巨大的熔岩从地下深处喷涌而出导致地壳断裂。Freshwaterbegantoaccumulateonthefloorofthisriftandachainoflakesdeveloped.淡水在大裂谷的谷底位置大量聚集，由此形成了一串链状排列的大小湖泊。Theselakesarenowoneoftherichestfreshwaterhabitatstobefoundanywhere.如今这些湖泊为各种各样的淡水动物提供了栖息地。Onesinglefamilyoffishhere-thecichlids-hasevolvedintomorethan1,500differentspecies.一个独特的鱼类家族——慈鲷在这里繁衍兴盛，已经进化出1500多个不同种类。Thismightlooklikeparadise,butcompetitionbetweenthesecichlidspeciesisintense.这里仿佛世外桃源一般，其实不同种类的慈鲷之间竞争异常激烈。Thiscrowdedworldisadangerousone.这片拥挤的水下世界，危机四伏。Babyfish,afterall,makeatastymeal.毕竟，幼鱼可是不错的美味。So,manycichlidmothershavedevelopedaveryeffectivewayofkeepingtheiroffspringsafe.许多慈鲷妈妈进化出一套高效的育儿措施来确保幼鱼的安全。Theyusetheirmouthsasamobilenursery.它们把大嘴当成移动的育儿所。It'sasafehavenwherethefrycanstayuntildangerhaspassed.—旦遇到危验，慈鲷幼鱼可以一直躲在妈妈嘴里享受庇护。Whenthecoastisclear,shereleasesthem.当危机解除，妈妈会再把幼鱼吐出来。Thiskindofbehaviourstartswhenthecichlidfemalepicksuphernewlylaideggsandholdstheminhermouthtokeepthemsafe.这种行为源于慈鲷妈妈在新产下卵时就会将其含入口中提供保护。Duringspawning,hermateflasheshisyellowtailspotstoencouragehertokeeplaying.在繁殖期，雄性慈鲷会不断闪动尾部的黄色斑点鼓励雌性持续产卵。Aseachbatchofeggsemerges,shescoopsthemup.当鱼卵产出后，慈鲷妈妈迅速含起鱼卵。Butthiscouplearebeingwatchedbycuckoocatfish.但这对慈鲷的举动全部被监视到了，它就是密点歧须鮠。Theyworkasaganganddevourasmanycichlideggsastheycanfind.密点歧须鮠成群结队地扫荡，肆意吞食能发现的慈鲷鱼卵。Then,inthemiddleofallthisactivity,oneofthecatfishalsospawns.在一片嘈杂和混乱中，其中一条密点歧须鮠也开始产卵。Thecichlidmothercollectseveryeggshecansee.慈鲷妈妈匆忙收集着所有鱼卵。Now,byherself,shemustwaitwhiletheeggsinhermouthdevelop.现在它要独自静静等待鱼卵在自己的嘴里发育。Itwilltakethreeweeks.这需要大概三周时间。Shedoesn'teatthroughoutthatentiretime.慈鲷妈妈在这期间始终不吃不喝。But18dayslater,somethingisnotright.18天之后，好像有情况不太对劲。Thefemaleblowsoutheryoungbeforethey'refullyreadytoemerge.慈鲷妈妈居然把没有发育成熟的鱼卵直接吐了出来。Andtheyarefollowedbyyoungcuckoocatfishthreetimesthesizeofherownbabies.紧接着它的嘴中赫然出现了密点歧须鮠的幼鱼，它们的个头是慈鲷幼鱼的3倍。Shemayhaveasmanyassixoftheminhermouth.它的嘴里可能有多达6条密点歧须鮠。Andnowtheybegintoeatthecichlidbabies.现在，它们开始狼吞虎咽抢食慈鲷鱼卵。Thefemalecichlidtreatsthebabycatfishasiftheywerehers.雌性慈鲷把密点歧须鮠幼鱼当成了自己的亲生孩子。Theyaretrulycuckoosamongfish!它们是鱼类中如假包换的“杜鹃”！TheforcesthatcreatedtheGreatRiftValleycontinuetoshapeAfrica'slandscapeeventoday.曾经鬼斧神工创造出东非大裂谷的自然力量，至今仍在塑造着非洲的地貌。AtweakspotsintheEarth'scrust,moltenrockcontinuestoerupt.在地壳的许多薄弱地点，炽热的岩浆仍旧在喷涌而出。Therearesome200volcanoesonthecontinentmanyofthemactive.非洲大陆拥有大约200座火山，其中许多都是活火山。Theymaybringdestructionbutalso,eventually,fertility.它们可能会带来破坏，但最终会是沃土。ThisisOlDoinyoLengai.这是伦盖伊火山。Forthepast400,000years,ashfromthisgreatvolcanohasfallenonthesurroundingsavannasoftheSerengetiandgreatlyenrichedthem.在过去的40万年里这座巨型活火山不断喷发火山灰，铺天盖地般撒落在塞伦盖蒂草原上滋养着这里的土壤。Thisisthebestgrazingonthecontinent.这是非洲大陆最好的草场。Onitlivetheworld'slargestherdsofmigratinganimalsandthey,inturn,sup