SeetheDifference

Haveyoueverheldalizard?Itsbodytemperatureislikelylowerthanyours.Youprobablywouldn’tfeeladifference.Butyoucanseeitintheseimagestakenwithaspecialcamera.Theyshowhowmuchheatanobjectgives off.

hand

lizard

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Thiselephantcoolsdownbyfanningits ears.  

Thisspider’sbodyiscoolerthanits environment. 

Lookattheimageofahandholdingalizard.Thebrightredofthehandshowsawarmbodytemperature.Thisistrueeventhoughtheairarounditiscooler.Thelizardshowsupmostlyasblue.Beforebeingheld,itwasdarkblue,likethebackground.Itsbodytemperaturewasthesameastheairaround it.


Butwhathappensasthelizardandthepersontouch?Thelizardgetsheatfromtheperson’shand.Itsbodyiswarming.Itsfeetandlegsshowupasgreenand yellow.

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Thiscatmakesitsownbodyheat.Itleavesbehindatrailofwarm pawprints. 

Watchasapersonleaveswarmfootprintsonacold floor.  

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gharial

Thisgharialsoaksupthesun’srays.Thenitstemperaturebeginsto rise.  

Foodprovidesthematerialstogrow.Italsorepairsdamagedcells.Ifyoucutyourfinger,newcellsgrowandhealit.Thenewcellscomefromfood.Foodalsoprovidesenergy.Andenergyproducesheat.Inthisway,ananimal’sbodyislikea furnace.

ALivingFurnace

Whycansomeanimalskeepthesamebodytemperaturewhileotherscannot?Theansweris  metabolism.


Metabolismisallofthechemicalreactionsthattakeplaceinthebody.Tiny moleculescombineandbreakapartinbodycells.Theyformnewsubstances.Mostofthishappensasfoodbreaks down. 


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meerkats

Thesemeerkatsdon’tneedtowaitforthesun.Theycontroltheirownbody heat. 

flamingos

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Someoftheseflamingoshaveonelegthatishotterthantheother. Whenaflamingostandsononeleg,thatleglosesheat,whiletheotherlegistuckedupnexttoitsbodykeeping warm.

Thefasterananimal’smetabolism,themoreenergytheanimalhasforkeepingwarm.Anendotherm’smetabolismisfast.Forbirdsandmammals,itisfastenoughtoproduceconstantwarmth.Thisallowstheanimaltokeepitsbodytemperaturehigh.Birdshavethefastestmetabolismandabodytemperatureof 40oCto 42oC (104oFto 108oF).Canyouthinkofareasonwhybirdsneedafastmetabolism?Thinkabouthowbirdsmove.Thehighrateofmetabolismmakestheenergybirdsneedto fly.