▁North ▁America , ▁the ▁Pale o - Ind ians , ▁are ▁believed ▁to ▁have ▁h unted ▁these ▁last ▁two ▁species ▁( occ ident alis ▁and ▁anti qu us ), ▁but ▁did ▁not ▁rely ▁on ▁them ▁to ▁the ▁ex clusion ▁of ▁other ▁large ▁her b iv orous ▁m amm als ▁such ▁as ▁m amm oth s , ▁m ast od ons , ▁cam els , ▁horses , ▁and ▁ground ▁sl oth s . ▁Ar ound ▁ 1 1 , 0 0 0 – 1 0 , 0 0 0 ▁years ▁ago , ▁however , ▁the ▁majority ▁of ▁the ▁large ▁game ▁species ▁in ▁North ▁America ▁became ▁ext inct , ▁possibly ▁due ▁to ▁over h un ting , ▁or ▁some ▁combination ▁of ▁these ▁and ▁other ▁factors . ▁One ▁of ▁the ▁few ▁large ▁surv iv ors ▁was ▁B . ▁anti qu us , ▁but ▁its ▁average ▁size ▁decl ined ▁until ▁it ▁evol ved ▁into ▁the ▁smaller ▁modern ▁American ▁b ison ▁around ▁ 5 , 0 0 0 ▁years ▁ago . ▁ ▁Native ▁American ▁pla ins ▁b ison ▁hunting ▁The ▁modern ▁American ▁b ison ▁is ▁split ▁into ▁two ▁sub species , ▁the ▁wood ▁b ison ▁in ▁the ▁bore al ▁for ests ▁of ▁what ▁is ▁now ▁Canada , ▁and ▁the ▁pla ins ▁b ison ▁on ▁the ▁pra i ries ▁extending ▁from ▁Canada ▁to ▁Mexico . ▁The ▁pla ins ▁sub species ▁became ▁the ▁dominant ▁animal ▁of ▁the ▁pra i ries ▁of ▁North ▁America , ▁where ▁b ison ▁were ▁a ▁ke yst one ▁species , ▁whose ▁gra zing ▁and ▁tram pling