Ranchers in the most remote parts of Eastern Oregon don't understand how or why so many cattle in the region have died through mutilation that includes surgical-like incisions, but not a trace of blood left behind. More than four hours south of Pendleton is Princeton, where a couple of years ago another cow was found dead — sliced up and mutilated, yet bloodless. Local residents made their rounds through the area looking for any clues or tracks that could lead to a conclusion, but they kept coming up empty. A local butcher even said he could not explain how it happened.
And this summer at the expansive 140,000-acre Silvies Valley Ranch, five young Hereford bulls were found dead, with their tongues and genitals removed and no tracks left behind. National Geographic interviewed a rancher who claims to have seen a bright light in the sky one night before one of his cattle was mutilated with no tracks in the snow, nor a trace of blood. He believes aliens abducted his cow, took it into space, removed its genitals and dropped it back onto the property where they found it.

Silvies Valley Ranch is nearly the size of Chicago. This summer, five young purebred bulls were cut down in their prime. Colby Marshall is the vice president of the ranch.
To understand what happened better, we rattled up a two-track U.S. Forest Service road.
“And we’re gonna drive in here,” Marshall said, “oh a little ways and then we’ll get out and take a little walk to where one [of] the bulls was found. And the carcass is still there.”
These animals were found bloodless, with their tongues and genitals precisely removed.

Whatever or whoever the cause, what’s clear is it isn’t bears, wolves, cougars or poisonous plants. Nor were the animals shot.
The FBI won’t confirm or deny it’s looking into the killings.
You may never have been out that way, but I have, many times, for zoological work. And I can tell you that in that country, everything leaves tracks - wolves, coyotes, even porcupines. I've tracked porcupines right to the juniper they're resting in, over the years. Unquestionably, these are real mysteries. I can understand why some have taken to viewing the cattle mutilations as the work of some alien entities, as there are no tracks or other evidence indicating human or animal involvement.