How The Removal Of A 'Nuisance' Predator Wreaked Havoc On Yellowstone National Park's Ecosystem

In the 1800's the Rocky Mountain West area of the USA that now includes Yellowstone National Park, was teeming with gray wolves. However they were considered nuisance predators who killed livestock and therefore, actively hunted down. By the time the National Park was established in 1827, the number of gray wolves had diminished substantially, a trend that continued thanks to a government predator control program that ensured that by 1926, there were none left.