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Predator Control is a Risky Road

Matt Skoglund

Posted March 6, 2012

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Wolf and Grizzly Bear in Yellowstone

A grizzly bear and a gray wolf in Yellowstone National Park.


A recent article in High Country News extols the virtues of controlling predators (e.g., wolves and bears) to boost ungulate populations (e.g., moose and caribou) in Alaska. It is an interesting article, and the author was thoughtful in her analysis of the issue.

But there was nary a mention of the ecological benefits that come with having top predators on the landscape, and thus I write to tell the infamous “rest of the story.”

Just a few dozen miles south of where I’m writing is Yellowstone National Park, where one of the greatest examples of the importance of top predators – the reintroduction of gray wolves – continues to unfold.  

By the 1930s, wolves had been eradicated from the West. They were then reintroduced into Yellowstone and central Idaho in 1995 and 1996. In the decades between their eradication and reintroduction, Yellowstone changed.

Coyote numbers skyrocketed, and then pronghorn antelope numbers dropped. Elk numbers soared (and elk behavior changed), and then streamside trees and bushes became less common. Without streamside vegetation, beaver numbers dropped, songbird numbers dropped, and less shade was provided along streams for coldwater fish species such as Yellowstone cutthroat trout.

Without wolves performing their role on the landscape, things began to fall out of whack.

And, then, following the reintroduction of wolves in 1995-96, Yellowstone again began to change. Coyote numbers decreased, and pronghorn numbers increased. The elk population dropped to healthier numbers, and elk again began behaving like wild elk. Streamside trees and bushes sprouted, beavers returned, songbird numbers increased, and all sorts of species (from grizzly bears to eagles) started scavenging on wolf-killed carcasses.

The return of wolves to Yellowstone is a powerful story about nature’s need for apex predators on the landscape – and a striking cautionary tale about what can happen when we remove them.

And the story is not limited to wolves and Yellowstone. As we continue to kill off apex predators (e.g., sharks), more and more research shows that the loss of such predators greatly affects the ecosystems where those carnivores once lived.

Wolves and bears, just like elk and deer, need to be managed (and the above article discusses reducing predator numbers, not eradicating them), but the larger point is that we need to appreciate the ecological importance of top predators, and our management practices should ensure that the populations of such predators are sufficient enough that they are able to meaningfully play their role on the landscape over the long term.

But while the science is abundantly clear that top predators are important for healthy functioning ecosystems, the social values involved are murkier. While some want to see large carnivores and healthy intact ecosystems, others would prefer inflated game populations. For me, as a hunter and angler, I’ll cast my vote for the former – for wildness – as there are enough neutered landscapes out there that I don’t want to see the Northern Rockies added to that list. But those are my values, and while I hope others will agree that robust populations of wolves and grizzlies belong in the Northern Rockies, I understand that others may – and, of course, have every right to – feel differently.

Like I said, it’s murky, and these questions are more sociopolitical-based than they are science-based, and they will continue to play out for years to come in Alaska, the Northern Rockies, and other places.

But as we grapple with these big questions, there is no more cogent voice to influence our thinking than that of the great hunter-angler-conservationist Aldo Leopold, who wrote the following many decades ago:

In those days we had never heard of passing up a chance to kill a wolf. In a second we were pumping lead into the pack, but with more excitement than accuracy: how to aim a steep downhill shot is always confusing. When our rifles were empty, the old wolf was down, and a pup was dragging a leg into impassable slide-rocks.

We reached the old wolf in time to watch a fierce green fire dying in her eyes. I realized then, and have known ever since, that there was something new to me in those eyes - something known only to her and to the mountain. I was young then, and full of trigger-itch; I thought that because fewer wolves meant more deer, that no wolves would mean hunters' paradise. But after seeing the green fire die, I sensed that neither the wolf nor the mountain agreed with such a view.

Since then I have lived to see state after state extirpate its wolves. I have watched the face of many a newly wolfless mountain, and seen the south-facing slopes wrinkle with a maze of new deer trails. I have seen every edible bush and seedling browsed, first to anaemic desuetude, and then to death. I have seen every edible tree defoliated to the height of a saddlehorn. Such a mountain looks as if someone had given God a new pruning shears, and forbidden Him all other exercise. In the end the starved bones of the hoped-for deer herd, dead of its own too-much, bleach with the bones of the dead sage, or molder under the high-lined junipers.

I now suspect that just as a deer herd lives in mortal fear of its wolves, so does a mountain live in mortal fear of its deer. And perhaps with better cause, for while a buck pulled down by wolves can be replaced in two or three years, a range pulled down by too many deer may fail of replacement in as many decades.

So also with cows. The cowman who cleans his range of wolves does not realize that he is taking over the wolf's job of trimming the herd to fit the range. He has not learned to think like a mountain. Hence we have dustbowls, and rivers washing the future into the sea.

We all strive for safety, prosperity, comfort, long life, and dullness. The deer strives with his supple legs, the cowman with trap and poison, the statesman with pen, the most of us with machines, votes, and dollars, but it all comes to the same thing: peace in our time. A measure of success in this is all well enough, and perhaps is a requisite to objective thinking, but too much safety seems to yield only danger in the long run. Perhaps this is behind Thoreau's dictum: In wildness is the salvation of the world. Perhaps this is the hidden meaning in the howl of the wolf, long known among mountains, but seldom perceived among men.


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Mia McPhersonMar 6 2012 04:35 PM

This is a terrific, informative article Matt. I absolutely love what Aldo Leopold wrote.

Just yesterday the Legislature in Utah passed a new bounty amount for Coyotes, with no scientific proof that exterminating them is actually doing what they think it should do.

David D. MorganMar 6 2012 10:37 PM

This story is told over and over. I believe at the beginning of the 20th century the mountain lions were wiped out in Arizona. The deer population spiked and then starved in large numbers. An ecosystem without top predators is not a healthy system.

Gary ChandlerMar 7 2012 03:14 PM

Killing Wolves Eliminates Barrier That Protects Our Food and Water

When attempting to manage wolf populations today, we must admit that the threat of prion contamination in our watersheds and food chain now poses a much greater risk to several industries, human health, and homeland security than our god-given wolves ever did. In fact, predators are one of nature’s few defense barriers against the deadly spread of prion disease.

Prions are a form of deadly protein that builds up in the cells and bodily fluids of people and animals afflicted with various forms of prion disease, including mad cow disease, chronic wasting disease, scrapie, and Creutzfeldt-Jakob Disease. Prions now are such a formidable threat that the United States government enacted the Bioterrorism Preparedness and Response Act of 2002 to halt research on infectious prions in the United States in all but two laboratories. Now, infectious prions are classified as select agents that require special security clearance for lab research. The intent is to keep prions and other dangerous biological materials away from terrorists who might use them to contaminate, food, water, blood, equipment, and entire facilities.

Dr. Stanley Prusiner earned a Nobel Prize in 1997 for identifying and studying deadly prions. President Obama awarded Prusiner the National Medal of Science in 2010 to recognize the growing significance of his discovery.

We now know that various forms of prion disease are already spreading around the world. Prion disease has been found in livestock and a variety of wildlife species across the U.S. and Canada (in gray wolf habitat). Reducing wolves in these areas below natural numbers will open the door even wider to the deadly spread of prion contamination in the environment.

The prion pathogen spreads through urine, feces, saliva, blood, milk, soil, and the tissue of infected animals (not to mention soil and water). With those attributes, prions obviously can migrate through surface water runoff and settle in groundwater, lakes, oceans, and water reservoirs. There is not a known cure for prion disease and allowing sick animals to wander the wild unchecked by wolves will further contaminate entire watersheds – increasing the pathway to humans, livestock, and wildlife downstream.

If prions must be regulated in a laboratory environment today, the outdoor environment should be managed accordingly. Wolves and other predators represent one of the few natural barriers to help minimize the spread of prions in the environment and within our food chain. Accelerating the killing of wolves and other predators for profit and pleasure is a foolish experiment in prion management and a reckless platform for safeguarding wildlife, watersheds, and homeland security. In fact, the National Park Service studied the issue and concluded that “as CWD distribution and wolf range overlap in the future, wolf predation may suppress disease emergence or limit prevalence.” (The Role of Predation in Disease Control: A Comparison of Selective and Nonselective Removal on Prion disease Dynamics in Deer.)

Now, more than ever, wolves are part of a healthy ecosystem and a healthy future. It’s time to develop a comprehensive prion-management strategy that maximizes safeguards for human health, food, water, and wildlife around the globe. The stakes are too high for fragmented and misguided prion policies. Just ask the Canadian cattlemen what a few prions did to their industry. Ask the U.S. cattle and dairy industries if they want to increase prion pathways in the watersheds that feed our public and private lands. My guess is that a prion in the soil or water doesn't care if it attaches to a cow, sheep, deer, elk, or human. It kills them all with the same efficiency. Dilution of this pathogen is not a solution. Ignoring this pathogen is not a solution because prions migrate, mutate and multiply. Let wolves and other predators do their job in the food chain without human interference. This is no time for people to play god.

Natalie KruseMar 7 2012 05:34 PM

Or, as Chief Seattle so succinctly put, whatever we do to the land and animals so we do to ourselves...Man will die of a great loneliness of spirit.

Matt SkoglundMar 14 2012 01:15 PM


Many thanks for the comments.

-- Matt

Comments are closed for this post.


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