You probably saw the headlines a couple weeks ago when a pack of wolves near Jackson, Wyoming, killed 19 elk in a single night. The event was blown up by CNN, The Guardian, and others as an example of the threat re-introduced wolf populations in the American west present to game and livestock. But I knew there must be more to it than just big bad wolf fears, so I started digging.
“We’re not sure what triggers surplus killing,” regional wildlife supervisor for the Wyoming Game and Fish Department John Lund told USA Today, “In many cases, predators will kill with the intent to eat, but in this case, something triggered, and they went crazy, and just took down each elk, and moved onto the next.”
Why do wolves kill more animals than they can eat? I think I just found out. And it’s not because they’re crazy.
The first thing this event reminded me of was the Chinese movie Wolf Totem. The story follows two young men who are sent from Beijing to Mongolia to teach rural herders about communism. Those herders live peacefully with the wolves who occasionally prey on their livestock, accepting it as nature’s balance. At one point in the movie, the wolves drive a herd of elk into deep snow, killing them, but also preserving their carcasses for future use throughout the harsh winter. It got me wondering about the incident in Wyoming, and whether storing meat for future use could be a real behavior of wolves here in North America.
Some initial Googling led me to this study, published by the Journal of Zoology, that found a correlation between the level of snowpack in a given year, and instances of wolves killing large numbers of prey. Could that really mean they’re storing kills for future consumption during times of harsh weather, when food may be hard to come by, as well as being key to survival? I called a wolf biologist to find out.
A former attorney who now works as the West Coast wolf organizer for the Center for Biological Diversity, Amaroq Weiss legally changed her name 13 years ago. "Amaroq" is an Inuktitut word for "wolf." When we spoke on Friday, news had just come through that OR4, a wolf she’d been working to save for a long time, had just been killed by the Oregon Department of Fish and Wildlife. She was audibly upset, and pulled no punches in her assessment of the surplus killing in Wyoming.
Folks who don’t like wolves, they like to call it "sport killing," or "thrill killing"—all a variation on the theme that, any time wolves kill more than they can eat at once, it’s evidence that wolves kill for sport, for the fun of it, or just to kill for killing’s sake. This is so very much not true. Any wolf biologist who has studied wolves in the wild will explain that elk hunting is really dangerous for wolves. Elk outweigh the wolves by five to seven times. I think the average female elk is 500 to 550 pounds, the average male elk is 700 to 750 pounds, while the average wolf is 95 to 110 pounds. It’s terribly dangerous, and it’s frequent that they get badly hurt or killed while hunting elk.
The studies that have gone on for Yellowstone over the years, looking at elk kill success rates show that wolves are only successful, on average, about 18 to 28 percent of the time. During very mild winters, where elk are in great condition, and still very robust, that’s when when wolves are successful only about 18 percent of the time. When you have a very severe winter, where elk are low on body weight, and can’t get the forage they need—they’re starving, they may be stuck in deep snow—only then might you see a success rate of about 28 percent. Wolves are not the killing machines we think they are.
And this winter has been very severe in Wyoming. That’s lead to a higher than normal number of elk taken by wolves—70 in the area near Jackson, alone—and has seen the state create elk feed grounds, where hay is spread out for elk to feed on. Weiss is critical of the use of feed grounds, suggesting they can encourage surplus killing by predators, and lead to other problems. “They’re a really misadvised thing to do,” she said. “If you draw in so many elk together, that really increases the risk of elk spreading disease to each other, and concentrating prey in that way is like a buffet, it’s proven to attract predators of all kinds—wolves, bears, mountain lions, you name it.”
So, local wolves found themselves presented not only with an elk herd weakened by the harsh winter, but also a tightly packed concentration of the animals. Conditions were favorable for a successful hunt, and they took advantage of it. “It ties into the whole understanding of why wolves target animals that are more vulnerable,” Weiss said. “They want to make it more likely that a hunt is going to be more successful, and less likely that the wolves are going to end up badly injured or killed in procuring the food that’s necessary for their survival. If wolves do find themselves in a position with a number of very vulnerable prey, they will kill more than they an eat at the moment. But, they will keep coming back and finishing that food source off.”
A contractor hired by Wyoming to spread hay on the feed grounds discovered 19 elk carcasses the next morning. The Game and Fish Department responded, removing the dead animals.
“In this case, not being able to eat the elk all at once, had the carcasses been left in the field, the wolves would have returned to gradually feed off the carcasses until all the uneaten bones and organs were gone,” Weiss said. “And other predators and scavengers would have fed, too.”
By removing the elk carcasses, that food source was eliminated. Now, the wolves will have to kill even more animals, possibly even engaging in dangerous elk hunts, in order to make up that amount of food. Weiss called the practice of removing surplus kills, “completely absurd. It’s a bad idea all around.” If more elk are killed by wolves this season, will the wolves be blamed?
In Wolf Totem, a local communist party official learns of the Mongolian wolves’ stash of elk carcasses, and takes them so he can be seen to be feeding a local village, which is skeptical of the party’s governance. In the end, the wolves are driven to extinction, rats take over, grasslands disappear, and so to does the traditional Mongolian way of life. It’s a heavy-handed parable, but one that does have some parallels with he reintroduction of wolves to Western states. If we want wolves to return to the wild, then we need to learn to understand and appreciate their behavior, even if that behavior is, at times, distasteful.