By the late 1970s, four main theories about the mutilation cases have emerged:
Police agencies in Alberta, Idaho, Montana, and Iowa did link some mutilation cases to satanic cults and ritual sacrifices. However, police investigating this theory found little supporting evidence and often ran into dead ends. The problem with this theory is that the mutilations are too widespread, span 30 years, and would require a large amount of resources to be executed throughout the world.
Black, unmarked, helicopters with tinted windows and powerful searchlights are often seen during a cattle mutilation wave. Conspiracy theorists believe the government is conducting top secret chemical warfare experiments.
On April 8, 1979, three police officers in Dulce, New Mexico, reported a mysterious aircraft which resembled a U.S. military helicopter hovering around a site following a wave of mutilation which claimed 16 cows. On July 15, 1974, two unregistered helicopters, a white helicopter and a black twin-engine aircraft, opened fire on Robert Smith Jr. while he was driving his tractor on his farm in Honey Creek, Iowa. This attack followed a rash of mutilations in the area and across the nearby border in Nebraska. The reports of “helicopter” involvement have been used to explain why some cattle appear to have been “dropped” from considerable height.
The weakness of this theory is that the government would have access to their own stock of cattle and would not necessarily need to use random cattle belonging to civilians. Also, the phenomena is too global to be conducted by any one government.
The first mutilation was reported in Colorado in September of 1967; the same year that Mothman terrorized and mutilated cattle in West Virginia, and a decade before the Chupacabra would be blamed for draining the blood and mutilating goats and livestock in Puerto Rico. So far none of these cryptids have been captured or photographed.
The Colorado Bureau of Investigation examined over 200 mutilation reports and concluded that the majority were caused by scavenging animals. They suggest that scavengers like ants and vultures go first for the softest dead tissue like the lips, eyes and rectum. They argue that once the cow’s heart stops pumping the blood will flow to and coagulate in the lowest portion of the body giving it an appearance of being drained of all blood.
However, the way in which the animal died is inconsistent with how a predator would kill it. Unlike animal attack, the flesh, adjoining the area where it has been removed, is smooth and clean as if cut with a searing or laser scalpel. As well, the areas chosen for removal are quite strange. Mainly the sexual, anterior digestive tract and sensory organs are affected. Also, no carrion eaters will touch the mutilated cow even though it has plenty of flesh still left to be eaten.
The absence of tracks, the mysterious nature of the act, and the coinciding UFO reports preceding mutilations suggest this is a sinister plan performed by aliens. Evidence at the scene of a mutilation suggest that the cattle were taken elsewhere by air, mutilated, and then dropped back near to where they were taken. UFOs are usually seen in the vicinity of cattle mutilations, and cattle are deathly afraid of them. Some ranchers have even reported seeing a UFO abducting the cattle in their fields.
There are more evidences to support this theory: cattle mutilations often occur in UFO Hotspots such as Northern New Mexico, and near Area 51, Nevada and two separate alien abductees have reported, under regressive hypnosis, seeing cattle taken into the alien craft and mutilated.
Various speculative theories have been proposed for the reason of such mutilation such as possible specific nutrient requisites, hormone procurement, species propagation (reproduction), and rote experimentation on mammalian populations.
UFO researcher Phillip S Duke even suggested that aliens have been using commercial cattle stocks to incubate and research the HIV/AIDS virus. He also speculates that mutilations of the ear are the result of aliens removing tracking implants. However, this theory is inconsistent with the origin of AIDS which has more likely be transmitted through zoonosis from primates who have higher genetic similarity to humans than cows.