<P> When Yellowstone National Park was created in 1872 , gray wolf ( Canis lupus ) populations were already in decline in Montana , Wyoming and Idaho . The creation of the national park did not provide protection for wolves or other predators , and government predator control programs in the first decades of the 1900s essentially helped eliminate the gray wolf from Yellowstone . The last wolves were killed in Yellowstone in 1926 . After that time , sporadic reports of wolves still occurred , but scientists confirmed that sustainable wolf populations had been extirpated and were absent from Yellowstone during the mid-1900s . </P>
when was the last wolf pack killed in yellowstone
1926