5 ▁MY A ) ▁in ▁California ▁and ▁Japan . ▁This ▁may ▁be ▁because ▁the ▁li pid ▁content ▁of ▁early ▁wh ale ▁b ones ▁was ▁too ▁low . ▁As ▁pre histor ic ▁wh ales ▁evol ved ▁to ▁live ▁in ▁pel ag ic ▁waters ▁and ▁d ive ▁deeper , ▁struct ural ▁changes ▁in ▁their ▁an atom y ▁included ▁increased ▁size , ▁reduced ▁b one ▁density ▁and ▁higher ▁li pid ▁content . ▁It ▁is ▁due ▁to ▁this ▁increased ▁li pid ▁content ▁that ▁led ▁to ▁the ▁establishment ▁of ▁chem os yn th etic ▁communities ▁in ▁the ▁deep ▁sea . ▁ ▁The ▁discovery ▁of ▁the ▁lim pet ▁O ste op elta ▁in ▁an ▁E oc ene ▁New ▁Zealand ▁t urt le ▁b one ▁indicates ▁that ▁these ▁animals ▁evol ved ▁before ▁wh ales , ▁including ▁possibly ▁inhab iting ▁Mes oz o ic ▁( 2 5 1 – 6 6 ▁MY A ) ▁re pt iles . ▁They ▁may ▁have ▁surv ived ▁in ▁see ps , ▁wood - falls ▁and ▁v ents ▁while ▁waiting ▁out ▁the ▁ 2 0 ▁million ▁year ▁gap ▁between ▁the ▁re pt iles ' ▁ext inction ▁and ▁wh ales ' ▁emer gence . ▁Another ▁possibility ▁is ▁that ▁these ▁foss ils ▁represent ▁a ▁prior , ▁dead - end ▁evolution ary ▁path , ▁and ▁that ▁today ' s ▁wh ale ▁fall ▁animals ▁evol ved ▁independently . ▁ ▁Anth rop ogen ic ▁effects ▁▁ ▁It ▁has ▁been ▁suggested ▁that ▁the ▁wh aling ▁industry ▁has ▁had ▁an ▁effect ▁on ▁the ▁bi ological ▁p ump ▁through ▁the ▁elim ination ▁of ▁many