灭绝动物与新物种

EnterthetimetunnelExtinctanimalBaijiWhiteDolphinTheDodotheGoldenToadTasmanianTiger

PassengerPigeon

PassengerPigeon(Ectopistesmigratorius)

HowdoyougofrombeingthemostcommonbirdspeciesinNorthAmericatobeingnothingmorethanasadfootnoteinAmericanhistory?

Well,ithelpsifyoutastegood.

Whilepassengerpigeonswerehuntedasacropnuisanceforyears,itwasn'tuntilpigeonmeatgotpopularthatthingstookaturnfortheworst.Italsosuredidn'thelpthatwestward-boundsettlerswerechoppingdownthebirds'habitatatanalarmingpace.

Overlessthan100years,thespeciesthatonceblackenedtheskyasitroamedinflocksnumberinginthebillionswassuddenlyinalotoftrouble.

ThelastpassengerpigeondiedinaCincinnatizooin1914.HernamewasMartha.TheDodoTheflightlessbird,nativetotheislandofMauritius,intheIndianOcean,wasknowntomankindforlessthan100years...butthat'sallittookforustoeradicatethespecies.Itwasn'tsomuchthathumanskilledthestubby,rotundbirdsdirectly,butourdecimationoftheirhabitatandfoodsourcedidanawfullottohastentheirdemise.Andthentherearethepigs,dogsandotherpredatorsthatweintroducedtotheisolatedisland,wheretheyravagedthebirds'nestsandgenerallyharassedthem.Thelastdododiedsometimeinthelate17thcentury.Sincethen,thebird(arelativeofpigeonsanddoves)hasbecomeaposterchildforextinctionandareminderofthehavocwecanwreakashumanbeings.ImageCredit:DCLtheGoldenToadThefirstrecordoftheGoldenToadwasbyherpetologistJaySavagein1966.Thetoad,recognizedbyitsbrilliantgoldenorangecolor,wasnativetothetropicalcloudforestswhichsurroundMonteverde,CostaRica.Nonehavebeenseensince1989.Itlastbredinnormalnumbersin1987,anditsbreedingsiteswerewellknown.In1987,duetoerraticweather,thepoolsdriedupbeforethelarvahadmatured.Outofpotential30,000toads,only29hadsurvived.In1988,onlyeightmalesandtwofemalescouldbelocated.In1989,asinglemalewasfound,thiswasthelastrecordofthespecies.Extensivesearchessincethistimehavefailedtoproduceanymorerecordsofthegoldentoad.TasmanianTigerThethylacinelookedlikesomethingofacrossbetweenatiger(duetoitsstripes)andadog(intermsofitsbuild).However,itwasinfactacarnivorousmarsupial,completewithpouch.NativetoAustralia,thethylacinewaslastseenonthatmainlandover2,000yearsago.Thetigerwashuntedtoextinctionbytheindigenouspopulation,buthadasafehavenofsortsintheislandofTasmania...oratleastitdiduntilEuropeansshowedup.Theirheavy-handedhunting,promptedinpartbyfarmers'protectionoftheirlivestock,broughttheanimaltominimalistnumbersbytheearly20thcentury.Bythen,effortstoprotectitweretoolate.Thelastonewascaughtin1933anddiedthreeyearslaterinazooinHobart,AustraliaBaijiWhiteDolphinTheBaijiwhitedolphinisoneofthemostrecentspeciestofallvictimtohumancivilization.NativetotheYangtzeRiverinChina,thefreshwaterdolphinwasnearlyblindandquiteintelligent.A2006expeditionsearchedtheYangtzeforsixweeks,butdidn'tfindanyBaiji,markinganendtoaspeciesthathadbeenapartoftheriversinceancienttimes.Theaquaticmammalhadfallenpreytohuntersandfishermen,asfishingboats,completewiththeirentanglinggear,begantocrowdtheriverinthe1950sand'60s.Areportedsightingin2007raisedhopes,butmostscientistsarguethatifafewoftheBaijidostillexist,theirnumbersaremostlikelysosmallastomakethem"functionallyextinct,"meaningthey'rebeyondacomeback.ThenewspeciesLiger（狮虎兽）Giantsquid（大王乌贼）White-lippedkeelbacksnake（白唇游蛇）Anourafistulata（花蜜长舌蝠）Liger（狮虎兽）Ligersaremainlyunderhumaninfluenceorbehind,amalelionandafemaletigertheoffspring.Ligersinsizethanthelionsortigerstobebig,alsohavephysicalcharacteristicsbetweenthetwo;probabilitypregnantlionsandtigerslove,verylow,evenincaptivity,tiger,lion,thechancesofconceivingisonly1%to2%.Thecubsduetobecongenitallydeficientandotherreasons,thesurvivalrateisonlyabout1/500000.Accordingtostatistics,currentlytheworldsurvivingligersonlyabout20.Giantsquid（大王乌贼）Giantsquidisoneofthelargestinvertebrateworldbody,thebodyof6to13meters,butthelegendofthelargestsquid,whichcangrowupto18metersormore,weighing2000kg.TheireyesSurprisingly,diameterupto35cm;suckerdiameterisin8centimetersofabove.Giantsquidliveinthedeepsea,inordertofishforfood,cancapturepreyinthedarkwater.Itoftenanddiveintothedeepforagingspermwhalebattling,spermwhalesareoftenscarred,butinthestomachsofspermwhaleshavefoundremnantsofthekingcuttlefish.Peoplehaven'tseenstayathabitatgiantsquid.Itisonlythroughdeathorinjuryfloatingtotheseaorwashedupontheshoreofthecolossalsquidtoknowsomeinformationofthisanimal.White-lippedkeelbacksnake（白唇游蛇）White-lippedkeelbacksnake,whiteandyellowstripes,upperliphasabeardlikewhitewide-brimmed,bodycoveredthereddot.Thissnakeisperchedattheedgeofthestream,istorelyontoeatfrogsandsmallanimal.Growtoamaximumof80cmlong.Evergreenmoistforestvastdistributioninthe"greencorridor"incentralvietnam."White-lippedsnake",becauseitsupperliphasabeardlikethewhiteband,thesnakecangrowtomorethan2feet(80centimeters)longAnourafistulata（花蜜长舌蝠）AnourafistulatawasdiscoveredbyAmericanscientistNathanMochharaoftheUniversityofMiami.Anourafistulatatongueis1.5timesitsbody,afterthechameleon(thechameleoncanputyo