海豚介绍(英文版)
Hopefullyyoualreadyknowthatdolphinsarenotfish.Dolphinsarewarmbloodedmammalslikeus.Theybreathairthroughanostrilonthetopoftheirheadscalledablowhole.Becausedolphinsbreathair,theymustsurfaceperiodically.Fish,however,breathbyusinggillsunderwater,andthereforedonotneedtosurface.Manyfishalsohavescales,whichdolphinsdonothave.Instead,theskinofadolphinfeelsrubbery.Alayeroffat,calledblubber,undertheirskinkeepsthemwarm.Thelocomotionoffishanddolphinsisalsodifferent.Fishswimbymovingtheirtailsfromsidetoside(horizontally).However,dolphinsswimbymovingtheirtailsupanddown(vertically).Howmanykindsofdolphinsarethere?Thisquestionwillprobablyneverbeansweredcorrectly.Ashumans,wewanttoputeverythingweknowofintoagroup.Somepeoplelikelargegroupswithsomevariationandotherslikesmall,precisegroups.Noteveryoneagreesaboutwhatmarinedolphinsdeservetheirownspeciesnameandwhatonesdonot.Icurrentlyhave32speciesofmarinedolphinslisted.Iamprettysurethatthiscoversallthespeciesaccurately.MostpeopleagreethattherearesixspeciesofporpoisesandfivespeciesofriverdolphinsDolphinscanunderstandandinterpretsomewordsandactions,theycannotunderstanduswordforwordlikeintheTVshow.Eventhoughdolphinsmaynotunderstanduscompletely,theymighthavetheirownlanguages.Infact,manypeoplebelievethatdolphinscommunicatewithlanguages
海豚身上的仿生学有哪些
声呐就是利用海豚仿生学原理发明的!仿生学是人类一直使用的方法,如模仿海豚皮而构造的"海豚皮游泳衣"。潜水艇是怎么发明的呢?原来是人们从海豚身上得到了启示.海豚是在水里的,能潜到水底下,它是怎么做到的?难道它有潜水的工具吗?它又是怎么从水底航行的?为了弄清楚这个问题,科学家做了一次试验。在一个水流冲击力很大,水又深的地方,把海豚放进去,可是海豚依然能往前走。再这不久,又做了一次试验。这次是按海豚的形状做了一个潜水艇,又做了一个慢的潜水艇相比,发现圆头的跑的快。两次不同的实验,发现海豚能轻松地超过轮船,是因为海豚的头是圆弧形的,而恰恰圆弧形受到的阻力最小。科学家又经过反复观察,终于揭开了海豚为什么能飞速的升落。是因为海豚身体大,阻力小,能轻而易举的升落,用尾巴一拍打水,利用水的托浮力,逐渐上升,就可以飞速地升落了。科学家模仿海豚的形状,潜水艇改成圆的,这样潜水艇就可以很快行驶了,还能随意上升下降。海豚,让科学家走到潜水艇的最高境界。