Although cattle mutilations have been reported in the U.S. since the 1800s, the 1967 death of a horse named Lady in Alamosa, Colo., drew national attention to the mystery that remains unsolved.

The horse had been partially skinned, and her heart, brain, lungs, and thyroid gland had been surgically removed, not torn away as would have been the case if the death had been caused by a predator or scavenger following the work of an animal such as a coyote.

By the 1970s, increased cattle mutilations were more frequently reported, ones in which the cattle were missing their eyes, ears, anuses, utters, tongues and sex organs, and the mystery surrounding their deaths grew because no blood, no tracks and no footprints were left behind, leading ranches to conclude that their cattle were being killed by some kind of invaders in aircraft.

Credibility to the reports were increased after the Colorado Press Association voted the cattle mutilations story as the No. 1 story of 1975. More than 200 cattle mutilations had been reported by Colorado’s ranchers during the year.

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