The Wolves Are Back: Yellowstone National Park

Después de que fueran exterminados en los años 20 del siglo pasado, los lobos han regresado al Parque Nacional de Yellowstone. Ahora es posible observarlos en todo su esplendor en su hábitat natural.

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Molly Malcolm

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For thousands of years, wolves were among the most prolific predators of the western United States. They roamed through the region, coexisting harmoniously with the Native American people, who revered them. Then, in the 1800s, European settlers arrived in the area. With agricultural development, much of the wolves’ natural habitat was destroyed. Settlers perceived them as a threat to their livestock and killed them along with other predators, such as bears and pumas (or mountain lions, as they are better known there.) 


One of the areas in the western US historically populated by wolves was designated Yellowstone National Park in 1872, making it the first national park in the US. Stretching across the states of Wyoming, Montana and Idaho, it became known for its many geothermal features, particularly the geyser known as Old Faithful. However, the US government did not take steps to protect its native species and wolf numbers rapidly declined. By the 1920s they were eliminated from the area altogether. 



The loss of the wolves caused an imbalance in the ecosystem, which was not acknowledged until decades later. Finally, in 1995, wolves were gradually reintroduced to the park and since then their number has multiplied. To find out more, Speak Up contacted Dr. Nathan Varley, a wildlife biologist who, unusually, grew up in Yellowstone as the son of two park employees. Today, he is the co-founder of Yellowstone Wolf Tracker, a wildlife adventure company that offers guided tours to visitors interested in observing the wolves of Yellowstone in their natural habitat. Varley estimates that there are around 130 wolves currently living in the park. We began by asking him why Yellowstone is a unique place for wolf tracking. 

Dr. Nathan Varley (American accent): I think it’s America’s and perhaps the world’s best opportunity so far to experience wolves in the wild. It came quite proclaimed as a recovery effort initially, where wolves have been wiped out in Yellowstone over a century ago and then finally restored, brought back, so that all the main components to the Yellowstone community had been restored. And it really kind of paved the way for visitors to see them as well. And that’s been maybe the most exciting part, is that the average Yellowstone visitor, with a little help and luck, can actually go out and see wolves in the wild, which isn’t something that’s very prevalent in the world today, right? I mean, it’s possible in other places, but Yellowstone has really become quite well known for that internationally.


Wolves were once prolific in the area, until the late 1800s when they were killed in their droves. Varley explains why.   

Dr. Nathan Varley: Yellowstone is our oldest national park. It’s been around for 150 years. Very early on, it was just a wilderness park. Few people, except for Native Americans, resided there, and it had the full complement of wildlife species. But as it became more of a destination and more managed for that around human values, we saw that, particularly in the late 1800s or early 1900s, predators were thought of as sort of bad animals. And so doing your job back then was protecting good animals. So, getting rid of the bad animals. And so wolves and other predators, other carnivores particularly, were killed as a matter of practice, as a matter of policy. And so a lot of coyotes, mountain lions... those kinds of animals, were persecuted, and wolves were, in fact killed off entirely. So about the 1920s or so were the last historical sightings of known living wolves in Yellowstone. So we went for eighty-plus years or so without them. And it really changed the community because, of course, being top predators they have a large effect on other animals around them.


However, the elimination of the wolves had a damaging effect on the park’s ecosystem.   

Dr. Nathan Varley: In national parks and particularly Yellowstone, there’s a lot of emphasis on natural processes, particularly in modern management. Not back when wolves were killed off, but we’ve evolved a lot since then.  History includes all these major changes. So now we really value all wildlife that evolved in the Rocky Mountain ecosystem, and Yellowstone is a good place to find those, and find all the relationships that are still operating the way they had in time immemorial.  In terms of the actual conservation of the park, we’ve retraced our steps to the present and we’re kind of at the wildest point in terms of the ecosystem in the entire 150-year history as a national park, except for perhaps the very beginning. But even then there was a lot of wildlife being killed for all kinds of purposes. But now we have maybe the largest density of these controversial large carnivores, like wolves and mountain lions and grizzly bears, that we’ve ever recorded in the park’s history.


Wolves were finally reintroduced in the 1990s, but this was not without controversy, as Varley explains. 

Dr. Nathan Varley: There was a lot of interest and fascination in it. At the same time, there was a lot of fear. Wolves have quite a reputation that kind of has its roots back to our folklore, mythology, fairy-tale types of stories, for sure. And so they kind of came in with a lot of public relations problems, a lot of baggage. And they’re still controversial today for the same reasons. Part of it’s that fear and part of it’s that little seed that indeed wolves are a little bit of a challenge to live with. Not really on a large scale. Wolves are recovering in Europe as they are in much of North America, and that hasn’t shown to be like this crisis of destroying industries altogether and people dying and all that kind of thing. It’s really quite manageable. Like many wildlife species, you have to adapt to them as much as they have to adapt to us. And so while they were controversial, I think some of that has died away and particularly ranchers have kind of learned that we have to do business with wolves on the landscape.


However, the reintroduction of the wolves has had a positive impact.

Dr. Nathan Varley: The biggest impact is, I think, on the human psyche: that the people that come to see wolves and really celebrate their presence. And it’s spawned this incredible ecotourism industry. But in terms of the community itself, the act of being top predator for the wolf has been restored. They are having their influence on many other components of the system in terms of the herbivores being less numerous and having different behaviours. And that’s kind of neat, to restore that primordial sense of what Yellowstone and its landscape has always been. So whether you’re talking about wolves feeding scavengers or increasing the amount of vegetation in some places because of less of an influence of these large herbivores, you can really see a whole list of things that wolves have already noticeably affected throughout Yellowstone.


We then asked Varley what makes a top predator.

Dr. Nathan Varley: It’s a nuanced answer. Scientists have kind of shown us that the per capita predation rate is owned by the mountain lion. An individual mountain lion will kill more prey animals in, say, a given year than an individual wolf. They’re the top predator in my mind. But wolves operate in packs, and so they can become more numerous on the landscape. And therefore, the overall population level of predators probably belongs to them because of this ability to operate as a pack and make more kills as a group than, say, mountain lions. Your average interaction in the park for wolves and mountain lions is wolves chase a mountain lion up a tree and it ends there. But we have cases where wolves have been killed by mountain lions, too. And mountain lions have been killed by wolves, too. It’s not a common event. But those things do happen out in the real world of nature here.


Today wolves are a protected species, though that does not make them invincible! 

Dr. Nathan Varley: They’re a protected species and they enjoy the best protection within national parks. Natural mortalities predominate, which means wolf packs in competition with each other may end up killing one another. That’s a way in which they regulate their own population size. And so it has this effect of driving the population back down to some stable level.And they get killed by their prey. They attack very formidable animals in elk and bison, so they die that way as well. Even a park the size of Yellowstone cannot contain that many wolves at all times. And they venture outside the park, where human-caused mortality is significantly high, as it is in most places where wolves exist alongside humans. They die fairly readily being struck by cars, but mostly killed by hunters and trappers.


So do they pose a threat to humans? 

Dr. Nathan Varley: No. So that’s a quick and easy answer, that we have not had a single case where wolves have even injured a person in the Yellowstone area. Now, can we go back into history and find cases where wolves have killed and consumed a person? Yes, but the rate of that is so, so low that they’ve proven to be in terms of dangerous animals, that the deer that live right around us are actually more dangerous. They kill more people than wolves do. They just have a natural shyness around people and natural inclination to avoid people, to be very cautious. Probably the worst thing that can happen is wild wolves get used to human foods, like we start feeding them for all the wrong reasons, and they can become aggressive. And any animal can. If they start to associate a food source with people, then they can get aggressive about getting that. So as long as we keep wolves in the wild, they remain real safe to people, and we can recreate among them without any fear of them attacking.


We then asked Varley how wolves are tracked. 

Dr. Nathan Varley: Finding a set of tracks that you know are wolves and following them is always just this fun sense of discovery. And we rely heavily on optics. So, binoculars and high-powered spotting scopes are the real key to spot them over long distances. In Yellowstone wolves are shy and they might run away if you approach them.


So how similar are domestic dogs to wild canine species, such as wolves? 

Dr. Nathan Varley: Canine behaviour is similar enough that we can find these unusual associations of, say, dogs and coyotes, and theoretically dogs and wolves as well. Great stories like [Jack London’s] Call of the Wild are about that kind of assimilation. One of my favourite things with our guests, who maybe dreamed about seeing wolves for a long time and finally have the experience as they’re watching them: “Oh, well, they’re just like dogs.” It’s like, “Yeah, exactly.” The dogs that live with us really came from these wolves. And so you’re already familiar with these behaviours. Could a dog theoretically be assimilated into a wolf pack? It would probably be difficult. They would treat it like another wolf. But that might be as in a competitive sense, in that that dog’s got to be pretty tough and maybe have some lucky situations where it can interact with the wolves in a way that they’ll accept it rather than kill it. Because that’s what they’re apt to do with a foreigner when they encounter another wolf on the landscape. They don’t always bring it to the pack. They’ll actually drive it off or sometimes even kill it. So good luck to the dog! But theoretically, it is possible.

The Gray Wolf

There are three species and close to forty subspecies of wolf and they are found in North America, Europe, Asia and North Africa. The most common type is the gray wolf or timber wolf, the Latin name for which is Canis lupus. This is the wolf species that is found in Yellowstone National Park, but also across North America and Europe. In fact, dogs are considered Canus lupus, as despite domestication they have remained closely related to wild wolves as a species. The reason that the gray wolves have not interbred with other species is that they rarely become isolated and can find others of their species across enormous distances.


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Este artículo pertenece al número de january 2024 de la revista Speak Up.

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