▁thousand ▁years ▁ago ▁( ky a ), ▁during ▁the ▁last ▁gla cial ▁maximum . ▁The ▁exact ▁boundaries ▁of ▁the ▁two ▁sub species ’ ▁ranges ▁remain ▁undefined ▁due ▁to ▁lack ▁of ▁data . ▁Based ▁on ▁current ▁evidence , ▁the ▁Sh i ho ▁sub species ▁is ▁distributed ▁in ▁the ▁eastern ▁Pacific ▁Ocean , ▁and ▁the ▁N ais a ▁sub species ▁ ▁en comp ass es ▁the ▁central / western ▁Pacific ▁and ▁Indian ▁O ce ans , ▁as ▁well ▁as ▁the ▁Atlantic ▁Ocean . ▁It ▁appears ▁as ▁though ▁the ▁Pacific ▁Ocean ▁acts ▁as ▁a ▁semi ‐ per me able ▁bar rier ▁between ▁the ▁two ▁sub species , ▁allowing ▁occas ional ▁migration ▁and ▁mixing ▁between ▁the ▁eastern ▁and ▁western ▁Pacific ▁Ocean , ▁but ▁keeping ▁the ▁populations ▁separate ▁enough ▁to ▁drive ▁this ▁different iation . ▁ ▁The ▁Atlantic ▁cla de ▁is ▁thought ▁to ▁have ▁diver ged ▁from ▁the ▁N ais a ▁approximately ▁ 1 2 . 5 ▁k ya , ▁however ▁this ▁split ▁is ▁supported ▁by ▁mit och ond rial ▁DNA ▁only , ▁and ▁not ▁nuclear ▁DNA . ▁Further ▁analysis ▁is ▁required ▁to ▁clarify ▁whether ▁the ▁Atlantic ▁Ocean ▁and ▁central / western ▁Pacific ▁and ▁Indian ▁O ce ans ▁pilot ▁wh ales ▁may ▁also ▁be ▁sufficiently ▁distinct ▁to ▁be ▁considered ▁sub species . ▁ ▁The ▁Atlantic ▁and ▁Indian / western - central ▁Pacific ▁types ▁are ▁also ▁diver ging ▁from ▁each ▁other , ▁with ▁the ▁Beng uela ▁Current ▁off ▁the ▁coast ▁of ▁South ▁Africa ▁separ ating ▁the ▁two . ▁ ▁Description ▁ ▁Short - f inned ▁pilot ▁wh ales ▁are