ison ▁her d ▁is ▁desc ended ▁from ▁a ▁rem nant ▁population ▁of ▁ 2 3 ▁individual ▁b ison ▁that ▁surv ived ▁the ▁mass ▁sla ugh ter ▁of ▁the ▁ 1 9 th ▁century ▁by ▁hiding ▁out ▁in ▁the ▁Pel ican ▁Valley ▁of ▁Y ellow stone ▁Park . ▁In ▁ 1 9 0 2 , ▁a ▁capt ive ▁her d ▁of ▁ 2 1 ▁pla ins ▁b ison ▁was ▁introduced ▁to ▁the ▁L amar ▁Valley ▁in ▁Y ellow stone ▁and ▁managed ▁as ▁liv est ock ▁until ▁the ▁ 1 9 6 0 s , ▁when ▁a ▁policy ▁of ▁natural ▁reg ulation ▁was ▁adopted ▁by ▁the ▁park . ▁Many ▁of ▁the ▁national ▁par ks , ▁in ▁particular ▁the ▁Y ellow stone ▁National ▁Park , ▁are ▁a ▁direct ▁result ▁of ▁the ▁gu ilt ▁that ▁many ▁felt ▁regarding ▁the ▁buff alo ▁sla ugh ter ▁of ▁the ▁Great ▁Pla ins . ▁ ▁The ▁Ant el ope ▁Island ▁b ison ▁her d ▁is ▁an ▁isolated ▁b ison ▁her d ▁on ▁Ut ah ' s ▁Ant el ope ▁Island , ▁and ▁was ▁founded ▁from ▁ 1 2 ▁animals ▁that ▁came ▁from ▁a ▁private ▁ran ch ▁in ▁Texas ▁in ▁the ▁late ▁ 1 8 0 0 s . ▁The ▁Ant el ope ▁Island ▁b ison ▁her d ▁fl uct u ates ▁between ▁ 5 5 0 ▁and ▁ 7 0 0 , ▁and ▁is ▁one ▁of ▁the ▁largest ▁public ly ▁owned ▁b ison ▁her ds ▁in ▁the ▁nation . ▁The ▁her d ▁contains ▁some ▁unique ▁gen etic ▁tra its ▁and ▁has