For the next several decades, elk cycled through population booms and collapses along with climate fluctuations; hard winters left the ground littered with hundreds of the carcasses of elk that had starved to death. Then, between 1995 and 1997, wildlife officials reintroduced 41 wolves to Yellowstone.

The history of elk in Yellowstone is a saga of dramatic population shifts and controversial management. In the early 20th century, elk numbers surged after predators like wolves were eliminated, leading to massive overgrazing that devastated the park's vegetation, particularly willow and aspen trees. To control this, rangers began a "direct reduction" program in 1934, shooting thousands of elk to protect the range. This changed significantly in 1995 with the reintroduction of gray wolves. Since the wolves' return, the elk population has dropped from a peak of nearly 20,000 to a more sustainable level of around 5,000 to 8,000. This "trophic cascade" has allowed trees to regrow and biodiversity to flourish. Today, the elk are healthier and more alert, though they face new challenges in 2026, such as the spread of Chronic Wasting Disease (CWD), which managers are closely monitoring to prevent a potential second collapse of the herd.