Theseremarks，Imaybepermittedtoadd，directlybearonthecaseoftheSiberiananimalspreservedinice。Thefirmconvictionofthenecessityofavegetationpossessingacharacteroftropicalluxuriance，tosupportsuchlargeanimals，andtheimpossibilityofreconcilingthiswiththeproximityofperpetualcongelation，wasonechiefcauseoftheseveraltheoriesofsuddenrevolutionsofclimate，andofoverwhelmingcatastrophes，whichwereinventedtoaccountfortheirentombment。Iamfarfromsupposingthattheclimatehasnotchangedsincetheperiodwhenthoseanimalslived，whichnowlieburiedintheice。AtpresentIonlywishtoshow，thatasfaras_quantity_offood_alone_isconcerned，theancientrhinocerosesmighthaveroamedoverthe_steppes_ofcentralSiberiathenorthernpartsprobablybeingunderwaterevenintheirpresentcondition，aswellasthelivingrhinocerosesandelephantsoverthe_Karros_ofSouthernAfrica。
IwillnowgiveanaccountofthehabitsofsomeofthemoreinterestingbirdswhicharecommononthewildplainsofNorthernPatagonia：andfirstforthelargest，orSouthAmericanostrich。Theordinaryhabitsoftheostricharefamiliartoeveryone。Theyliveonvegetablematter，suchasrootsandgrass；butatBahiaBlancaIhaverepeatedlyseenthreeorfourcomedownatlowwatertotheextensivemud-bankswhicharethendry，forthesake，astheGauchossay，offeedingonsmallfish。Althoughtheostrichinitshabitsissoshy，wary，andsolitary，andalthoughsofleetinitspace，itiscaughtwithoutmuchdifficultybytheIndianorGauchoarmedwiththebolas。Whenseveralhorsemenappearinasemicircle，itbecomesconfounded，anddoesnotknowwhichwaytoescape。Theygenerallypreferrunningagainstthewind；yetatthefirststarttheyexpandtheirwings，andlikeavesselmakeallsail。OnonefinehotdayIsawseveralostrichesenterabedoftallrushes，wheretheysquattedconcealed，tillquitecloselyapproached。Itisnotgenerallyknownthatostrichesreadilytaketothewater。Mr。KinginformsmethatattheBayofSanBlas，andatPortValdesinPatagonia，hesawthesebirdsswimmingseveraltimesfromislandtoisland。Theyranintothewaterbothwhendrivendowntoapoint，andlikewiseoftheirownaccordwhennotfrightened：thedistancecrossedwasabouttwohundredyards。Whenswimming，verylittleoftheirbodiesappearabovewater；theirnecksareextendedalittleforward，andtheirprogressisslow。OntwooccasionsIsawsomeostrichesswimmingacrosstheSantaCruzriver，whereitscoursewasaboutfourhundredyardswide，andthestreamrapid。CaptainSturt，[11]whendescendingtheMurrumbidgee，inAustralia，sawtwoemusintheactofswimming。
Theinhabitantsofthecountryreadilydistinguish，evenatadistance，thecockbirdfromthehen。Theformerislargeranddarker-coloured，[12]andhasabiggerhead。Theostrich，Ibelievethecock，emitsasingular，deep-toned，hissingnote：whenfirstIheardit，standinginthemidstofsomesand-hillocks，Ithoughtitwasmadebysomewildbeast，foritisasoundthatonecannottellwhenceitcomes，orfromhowfardistant。
WhenwewereatBahiaBlancainthemonthsofSeptemberandOctober，theeggs，inextraordinarynumbers，werefoundalloverthecountry。Theylieeitherscatteredandsingle，inwhichcasetheyareneverhatched，andarecalledbytheSpaniardshuachos；ortheyarecollectedtogetherintoashallowexcavation，whichformsthenest。OutofthefournestswhichIsaw，threecontainedtwenty-twoeggseach，andthefourthtwenty-seven。
Inoneday’shuntingonhorsebacksixty-foureggswerefound；forty-fourofthesewereintwonests，andtheremainingtwenty，scatteredhuachos。