▁the ▁l ungs ▁and ▁air way . ▁However , ▁this ▁and ▁other ▁early ▁studies ▁of ▁sau rop od ▁e col ogy ▁were ▁fla wed ▁in ▁that ▁they ▁ignored ▁a ▁substantial ▁body ▁of ▁evidence ▁that ▁the ▁bodies ▁of ▁sau rop ods ▁were ▁heavily ▁per me ated ▁with ▁air ▁sac s . ▁In ▁ 1 8 7 8 , ▁pale ont ologist ▁E . D . ▁C ope ▁had ▁even ▁referred ▁to ▁these ▁structures ▁as ▁" f lo ats ". ▁ ▁Begin ning ▁in ▁the ▁ 1 9 7 0 s , ▁the ▁effects ▁of ▁sau rop od ▁air ▁sac s ▁on ▁their ▁supposed ▁aqu atic ▁l ifest yle ▁began ▁to ▁be ▁expl ored . ▁Pale ont olog ists ▁such ▁as ▁Co omb s ▁and ▁Bak ker ▁used ▁this , ▁as ▁well ▁as ▁evidence ▁from ▁sed iment ology ▁and ▁bi ome chan ics , ▁to ▁show ▁that ▁sau rop ods ▁were ▁primarily ▁terrest rial ▁animals . ▁In ▁ 2 0 0 4 , ▁D . M . ▁Hend erson ▁noted ▁that , ▁due ▁to ▁their ▁extensive ▁system ▁of ▁air ▁sac s , ▁sau rop ods ▁would ▁have ▁been ▁bu oy ant ▁and ▁would ▁not ▁have ▁been ▁able ▁to ▁sub merge ▁their ▁t ors os ▁completely ▁below ▁the ▁surface ▁of ▁the ▁water ; ▁in ▁other ▁words , ▁they ▁would ▁float , ▁and ▁would ▁not ▁have ▁been ▁in ▁danger ▁of ▁lung ▁collapse ▁due ▁to ▁water ▁pressure ▁when ▁sw imming . ▁ ▁Ev idence ▁for ▁sw imming ▁in ▁sau rop ods ▁comes ▁from ▁foss il ▁track ways ▁that