YojiOkatopulledonhisdivegear.Theunderwaterphotographergatheredhiswaterproofcameras.Thenhedoveintotheseaoffsouthern Japan.
Whenhereachedtheseafloor,hesawsomethingodd.Itwasagiantcircleinthesandthatwastwometers(six feet)wide.Thesandinthecenterlookedsmooth.Apatternofsymmetricalridgespileduparoundtheedgeofthe circle.
Okatotookpicturesofthesandsculpture.Whenhesharedhisphotos,otherdiverssaidthey’dseenthesemysteriouscircles,too.Yet,noonehadeverseenwhatmade them.
Searching
foraCause
Peoplehadtheoriesabouttheseseacircles.SomesaidtheyformedwhenaUFOlandedontheseafloor.Thespaceshipleftamarkinthesand,theysaid.Othersthoughtoceancurrentssculptedthesand.Themovingwatercouldpushthesandintoridges.Yet,thecirclesseemedtooperfectlyroundtobeformedbyshiftingwater currents.
Tosolvethemystery,Okatoteamedupwithscientistsandfilmmakers.Timeaftertime,theyreturnedtothedivesite.Theteamwatchedandwaitedtoseehowthecirclesformed.Diveafterdive,theysawnothingandswamawaywithoutany clues.
Apufferfishmovessandasitflapsitsfinsandswimsalongthe seafloor.
Yoji Okato
sand circle
Finally,theteamcaughttheartistintheact.Itwasn’tanalien,anditwasn’tanoceancurrent.Itwasamalepufferfish.Heswambackandforth.Themotionmadetinywaves.Thesewavesmovedthesand,formingacircle.Thenthefishusedhisfinstodigintothesand.Heflippedfinesandintothecenterofthecircle.Hedugdipsandbuiltridgesaroundtheedge.Finally,hecollectedbitsofshellsinhismouthandcarefullyplacedthemonthe ridges.
Asia
Japan
Apufferfishmovessandasitflapsitsfinsandswimsalongthe seafloor.
MysterySolved
Okato’steamdidn’tjustfindoutwhatbuildsthemysterioussea circles.Theylearnedwhythepufferfishbuilds it.
Whenafemalepufferfishswamby,themalezippedbackandforthinsidethecircletogetthefemalefish’sattention.Itworked.Shedecidedtolayhereggsinthecenterofthecircle.Ittookpatienceandalotofobservation,butOkatofinallysolvedthemysteryofthesea circles.
Apufferfishswimsbackandforthasitmakesasand circle.