Cattle mutilation
Cattle mutilation is the alleged killing and then subsequent mutilation of cattle. Sheep or horses have also been similarly mutilated, according to some accounts.
Mutilations include removal of parts of the mouth and hind regions, especially the anus and sexual organs.
Some attribute these mutilations to extraterrestrials, such as "bad" aliens. Others, including cryptozoologists, attribute them to malevolent alien creatures released by other aliens.
Skeptics, such as Robert T. Carroll, and many scientists hold that the apparent mutilations have completely natural and terrestrial origins: animals that have died from natural causes which have then been fed upon by a variety of scavengers, who tend to remove the eyes and softer internal organs first via the easiest access route—the mouth and anus. Some, however, have noted that ranchers and large-animal veterinarians have made distictions between normal predation and so-called "cattle mutilations."
The media often gives more attention to the more sensational and mysterious causes cited above. The persistence of the reports, however, typically by credible witnesses who prefer to remain anonymous or do not stand to benefit financially from such reports, remain an evidence in favor of the events.
See also: Anomalous phenomenon, chupacabra