Throughout the 1970s, a rash of bizarre incidents occurred in western states of the U.S. that involved the untimely deaths of cattle and other farm animals. Animals dying on farms is nothing new, but the manner in which they died was. These animals were often found with some of their organs removed, seemingly with medical instruments. They were also drained of nearly all their blood, without evidence of footprints (human or animal) in the area.

And sometimes, strange lights were witnessed in the skies over these scenes.

By the 2000s, thousands of these “cattle mutilations” (as they became known) had taken place, with the greatest number occurring in the 1970s in the states of Colorado and New Mexico. Though these freaky animal deaths remain unsolved, there are plenty of theories about them: natural decomposition, predators, satanic cults, covert government experiments, and alien experiments are among the most popular.

The first documented case of a cattle mutilation actually involved a horse. The King family were ranchers in southern Colorado who took great care of their livestock, so when they found their horse Lady dead in a field in 1967 they were quite surprised. Even more shocking was Lady’s condition.

The flesh had been stripped from Lady’s head, leaving the bone of her skull exposed. Several of her organs had also been removed with what appeared to be surgical precision, and there was very little blood left in the body.

Perhaps most perplexing was the fact that there were no human or animal footprints found anywhere near the corpse.

After Lady’s strange death, other livestock mutilations began to appear across the west. In addition to the bizarre manner in which the animals were usually found, witnesses reported that wild and domestic animals, including flies, steered clear of the corpses. The victimized animals also often had their tongues, genital organs, and rectums removed. Laboratory examinations of some of these animals showed some anomalies, such as elevated levels of zinc and phosphorous, but nothing that pointed to any explanation.

But many have offered their own explanations.

The number of cases grew to the point that politicians from Colorado and New Mexico lobbied the federal government to do something. In 1979, an FBI investigation named “Operation Animal Mutilation” opened. The Bureau of Alcohol Tobacco and Firearms (ATF) also conducted an investigation, as well as the states of Colorado and New Mexico. 

Each of the investigations consulted legitimate scientists as well as ranchers and farmers, most of whom came to the conclusion that the mutilations were the result of natural deaths and natural patterns of decay. For instance, the lack of blood was explained by the natural pooling of it, while the missing genital organs and rectums were explained by scavenging blowflies.

This probably explains many of the cases, but not all. Some of the mutilated cattle had no observable blood and many showed no signs of blowfly activity.

So, if many of these animals were killed by surgical precision, maybe it was the work of satanic cults?

This theory became popular in the wake of the Charles Manson Family murders. Other notable cults in the 1970s, such as Jim Jones’ People’s Temple, helped keep it alive. There were also two incidents in the fall of 1975 where groups of people wearing black robes were observed in rural Idaho, after which mutilated cattle were found in the area. Thanks to the “Satanic Panic” of the 1980s, belief in this theory continued into another decade.

But it would take a whole lot of cults to account for the thousands of mutilated livestock cases.

As is often the case with inexplicable events, UFOs and aliens became an explanation. In fairness to this theory, a number of respectable ranchers and farmers have claimed to have seen strange lights and unidentified flying objects moving in the skies above their mutilated life stock. The theory is that only alien technology could have made such precise incisions and that aliens are conducting some sort of experiments on our animals. In a number of these cases, “black helicopters” are seen along with the UFOs.

The black helicopter cases have led some to believe that the cattle mutilations are part of some major government conspiracy. The theory is that government has been experimenting on livestock as part of bioweapons programs. Advocates of this theory say that the presence of helicopters explains why there are often no footprints at the scenes of the mutilations. But it doesn’t explain why the government, with all its vast resources, would need to experiment on random, privately owned livestock.

Finally, there are those who think the mutilations are the work of chupacabras. Remember them?

Although cattle mutilation is still reported from time to time, the number of cases has dramatically decreased since the 1980s. Maybe whoever was doing it got what they wanted.