《贸易客源国概况》课件——3-5-2澳大利亚的国宝A National Treasure of Australia.pptx

ANationalTreasureofAustralia

Lecturer：GuoZhiwen

Platypus（?pl?t?p?s）isarareanimalontheearth,andalsoanationaltreasureofAustralia.

Platypusisoneofthemostprimitivemammals,itisnotfullyevolvedmammals,fewspecies,onlyplatypusinthesamegenus,isalsooneofthelowestmammals;Platypushascharacteristicsofmammal,reptile,birdandfish.Itlayseggsandalsofeeds.

Platypusinhabitsattheedgeofthewaterandlaystwotofoureggseachtime.Thecolorandsizeoftheeggsaresimilartopigeoneggs.ThebabyPlatypuslivesonitsmothersmilk.Sofar,theexactnumberofPlatypusinAustraliaisunknown.Platypussmouthandfeetarelikeducks,whileitsbodyandtailarelikebeavers.

Thewholebodyiscoveredwithsoftbrownthickshorthair,themouthiswideandflat,theshapeislikeducksbeak,thetextureissoft,likeleather.ThePlatypussbeakiscoveredwithnerves,whichcanreceiveradiowavesfromotheranimalslikearadarscanner.Therearewidegumsinthemouth,butnoteeth.Thetailislargeandflat,accountingfor1/4ofthebodylength.Itactsasarudderwhenswimminginthewater.

Adultplatypusis40-50cminlength.Itdefendsitselfwithvenom.Thevenomcankillsmallanimals,butitisnotfataltohumans.However,itcancauseseverepainandlastforweeksorevenmonths.Itisanocturnalcreatureandconsumesthesameamountoffoodasitsbodyweighteveryday.

Theplatypusisofgreatacademicsignificance.Afterhundredsofmillionsofyears,ithasneitherbeenextinctnorevolvedmuch.Itisalwaysinthetransitionalstageandfullofmystery.ThiskindofanimalisonlyproducedinAustraliaintheworld,butbecauseofthepursuitofspecimensandpreciousfur,manyyearsofindiscriminatefishinghasledtotheseriousdeclineofthepopulationandoncefacedthedangerofextinction.

Thankyou!