Investigators have been left baffled after dozens of cows have been killed in gruesome ways with some reported to have missing tails and vicious bite marks.
The bovine killings have happened in the White River National Forest area in Colorado with so far around 40 animals having been killed.
Park rangers initially thought wolves might be responsible, but now they're not so sure.
Colorado Parks and Wildlife region manager Travis Black says teams have found no evidence that wolves were responsible, reports the Express.
“It’s perplexing,” Black said. “We’re scratching our heads a little bit. We don’t know exactly what has occurred up there.”
The manager added that only a few of the cows had injuries that might indicate a wolf attack, and there is no evidence that whatever carried out the vicious attacks ever returned to their prey, which would be unusual for wolves.
He said investigators have used trail cameras and surveyed the area by flying overhead, but said: “We have no evidence of wolves in that area. That doesn’t mean they’re not there. Sometimes wolves can be difficult to locate.”
The mystery began in early October, when rancher Lenny Klinglesmith discovered about 18 of his calves were killed in the area.
Investigators thought it might be wolves, but were left baffled as the state only has one confirmed pack of wolves in North Park, which is a 160.8 mile drive away from the rancher’s farm south of Meeker.
The attacks sparked an investigation by Colorado Parks and Rescue. During the investigation, two other possible explanations have emerged.
First is a type of bacterial infection. If the cattle were sick any sort of attack or chased by wolves, it could have exacerbated their illness and killed them, Black claims.
But when experts examined the dead cattle for such an illness, those results came back inconclusive as well. Microscopic lesions that typically indicate such an infection weren’t there, he said.
The second new possibility is that dogs used to protect livestock might have attacked or startled the cattle, Black claims. But those dogs aren’t generally in the area this time of year.
But not everyone is perplexed. Mr Klinglesmith, who owns LK Ranch with his wife Jackie, believes all his dead cows were the work of wolves.
He added they all suffered extensive trauma and damage to their flanks, bite marks on their heads and faces, some missing and damaged tails, and extensive bruising on both sides.
The rancher then added: “We’re trying to learn how to coexist with wolves like we’re going to need to, but I was preparing to share a calf or two here and there to feed their pack, be compensated, and do what I can to prevent conflict.
“When they come through and slaughter 18 calves and leave them to lie, they’re not holding up their end of the deal with coexistence.”
In Colorado, wolves are protected under state law and the federal Endangered Species Act.
Killing one of the animals can result in a $100,000 fine, up to a year in prison, and the potential loss of hunting privileges.