In the wake of recent cattle mutilations across the West, ranchers are asking who — or what — is responsible.

According to FBI records, thousands of killings and apparent mutilations of cattle have happened since the 1970s. In each case, a cow or bull is found dead with body parts such as eyes, tongues and genitals missing.

Ranchers and detectives have speculated widely about what’s happening, theorizing aliens, cult members, pranksters or even the CIA could be responsible.

The Capital Press sat down for an interview with retired award-winning Canadian veterinary pathologist Nick Nation, who has researched the issue.

In Alberta, Nation has analyzed the carcasses of mutilated cattle and, more recently, dismembered house cats. In both cases, he’s come to the same conclusion: scavenger animals, primarily coyotes, are responsible.

The interview has been edited for brevity and clarity.

CP: You started researching the issue of cattle mutilation in the 1980s. At the time, you came to the conclusion that scavengers were responsible for body part removal. Do you still believe that?

Nation: Yes. I’m still convinced coyotes and occasionally some other species, you know, birds, skunks, even mice, will do damage to these carcasses. It’s the bizarre nature of the appearance of the animal that gets people concerned that there may be some nefarious activity going on.

CP: Wouldn’t coyotes leave obvious bite marks? We hear from ranchers and detectives that the wounds usually look clean-cut.

Nation: That’s common in coyote predation, and it’s also a feature on the cats we’ve done a study on. The one thing that makes people think they’re dealing with malicious intent is that they think they’ve got a surgical-like or even laser-like cut. What we’ve found in predations known to be from coyotes scavenging a carcass is they’ll bite and then pull back, leaving what appears to be a straight-line cut. There are also little bite marks, but you have to look closely for them.

CP: How do you know the cases you’ve studied have definitely been coyotes?

Nation: The incidents were captured on video camera, or we used eyewitness accounts where the owner saw coyotes mutilating the animals.

CP: So why is it farmers often don’t find footprints? Shouldn’t there be coyote tracks?

Nation: That’s fair game, a fair comment. My experience is that you seldom get a person bringing in an animal in wintertime saying it was mutilated. And the reason is that the paw prints are right there in the snow, so (farmers) know what happened then. In the summer, paw prints aren’t as easy to spot.

Now, in hindsight, after working with a coyote specialist, I also wonder if some of that seasonality is also because that coincides with when adult coyotes are teaching pups of the year how to hunt and eat, going for the ends of the body where the skin is softest.

CP: For the sake of your argument, let’s say coyotes are removing body parts. That still doesn’t explain how the animals died in the first place.

Nation: Well, people often miss that 24-hour window (to examine the body after death).

Ranchers also get so concerned about mutilation they sometimes won’t get a necropsy done. The cow might have died of plant poisoning, a disease or a subtle metabolic condition.

My take-home message would be, no matter what you think happened to the animal, get it into a state diagnostic lab or a veterinarian. A dead animal can be seen as a loss, but it can be turned into an asset if the test hints at something like a parasite or nutritional problem you can deal with in the rest of your herd.

CP: Your theory isn’t as popular as theories of foul play. Why do you think that is?

Nation: Well, for one thing, coyotes and mice are not as exciting. If you can mix perversion and cults and the unknown, you can have a wonderful mix of a story there that people can let their imaginations run wild on. I’m not saying I have all the answers, but it’s sure more reasonable than Martians and ray guns.