The 1975 Colorado Cattle Mutilation Epidemic

In 1975, Colorado became the epicenter of the cattle mutilation phenomenon, with the state logging more reports than any other in the nation. Governor Richard Lamm requested an investigation by the Colorado Bureau of Investigation (CBI), marking the first time a state government officially addressed the phenomenon. The CBI investigated dozens of cases across the state but ultimately concluded that most could be attributed to natural causes, a finding that was immediately and vociferously disputed by ranchers and local law enforcement. Colorado's experience in 1975 encapsulated the fundamental tension in cattle mutilation research: scientists and federal investigators consistently attributed the injuries to scavengers and decomposition, while the people who discovered the carcasses — ranchers with decades of experience with livestock death — insisted that what they were seeing was unlike anything caused by natural predation. The 1975 Colorado wave also produced some of the phenomenon's most enduring mysteries, including reports of cattle found with broken limbs suggesting they had been dropped from a height, and instances of perfectly circular patches of depressed vegetation near carcasses.