▁empty ▁spaces ▁in ▁them ▁which ▁would ▁have ▁been ▁filled ▁only ▁with ▁air . ▁An ▁air - s ac ▁system ▁connected ▁to ▁the ▁spaces ▁not ▁only ▁light ened ▁the ▁long ▁ne cks , ▁but ▁effectively ▁increased ▁the ▁air flow ▁through ▁the ▁tra che a , ▁helping ▁the ▁cre atures ▁to ▁bre at he ▁in ▁enough ▁air . ▁By ▁evol ving ▁verte bra e ▁consisting ▁of ▁ 6 0 % ▁air , ▁the ▁sau rop ods ▁were ▁able ▁to ▁minim ize ▁the ▁amount ▁of ▁dense , ▁heavy ▁b one ▁without ▁sacrific ing ▁the ▁ability ▁to ▁take ▁sufficiently ▁large ▁breath s ▁to ▁fuel ▁the ▁entire ▁body ▁with ▁o xygen . ▁According ▁to ▁Kent ▁Stevens , ▁computer - mode led ▁reconst ru ctions ▁of ▁the ▁ske let ons ▁made ▁from ▁the ▁verte bra e ▁indicate ▁that ▁sau rop od ▁ne cks ▁were ▁capable ▁of ▁swe eping ▁out ▁large ▁feed ing ▁areas ▁without ▁need ing ▁to ▁move ▁their ▁bodies , ▁but ▁were ▁unable ▁to ▁be ▁ret ract ed ▁to ▁a ▁position ▁much ▁above ▁the ▁shoulders ▁for ▁expl oring ▁the ▁area ▁or ▁reaching ▁higher . ▁ ▁Another ▁proposed ▁function ▁of ▁the ▁sau rop ods ’ ▁long ▁ne cks ▁was ▁essentially ▁a ▁radi ator ▁to ▁deal ▁with ▁the ▁extreme ▁amount ▁of ▁heat ▁produced ▁from ▁their ▁large ▁body ▁mass . ▁Consider ing ▁that ▁the ▁met abol ism ▁would ▁have ▁been ▁doing ▁an ▁immense ▁amount ▁of ▁work , ▁it ▁would ▁certainly ▁have ▁generated ▁a ▁large ▁amount ▁of ▁heat ▁as ▁well , ▁and ▁elim ination ▁of ▁this ▁excess ▁heat ▁would ▁have ▁been ▁essential