“The idea that native wolves were ‘much smaller’ and ‘do not engage in lust killing’ is not substantiated by any scientific proof...The name Canis lupus irremotus is dated and no longer considered scientifically valid. It is now considered part of the subspecies Canis lupus nubilus, which includes wolves formerly present in the U.S. Great Plains and most of the western U.S. and currently still present in northeastern Canada. This subspecies is variable in size, but is not substantially smaller than Canis lupus occidentalis of western Canada, Alaska, Idaho, Montana, and Wyoming. Current subspecies designations are based primarily on genetics and skull morphology." - Gary Wiles, Washington Fish and Wildlife, author of the Washington Wolf Management Plan
Honestly, there is no 100% known answer when it comes to wolf genetics
If you don't want to read this entire article, here are some key points:
- Wolf genetics are so heatedly debated in the scientific community, information is always changing with new studies.
- Historical records are hard to believe, considering many settlers couldn't identify a wolf from a coyote, much less wolf subspecies.
- Subspecies = geographic variant within a species based off of physical - not so much genetic- differences. Subspecies can still breed with one another without compromising genetic integrity.
- Another subspecies of wolf, Canis lupus nubilis, or the Great Plains/ buffalo wolf, went extinct around 1920. It was much bigger than most of the lower 48 wolves, equitable or surpassing Canis lupus occidentalis or the McKenzie Valley wolf (the "wrong Canadian wolf").
- Scientific taxonomy dictates that the differences are so minute amongst subspecies - especially genetically- having different subspecies intermingle geographically doesn't affect the ecosystem or the genetic integrity of the wolves. If, however, you were to introduce red wolves to the west or gray wolves to the east, since those are two different species, yes it would likely make more of a difference.
- Canis lupus occidentalis was already making its way south, with several accounts dictating they'd already crossed the border before. Honestly, you can blame humans for that; the eradication of wolves in the lower 48 opened vast amounts of territory just waiting to eventually be grabbed by other wolves.
- Even if a "bigger" "wrong" subspecies was introduced from Canada... the ecological principle of Bergman's Rule states that animals are bigger in the north than the south due to resource allotment, so those "bigger" wolves will adjust to a different latitude.
- Subspecies cannot, by definition, be an illegal species to another subspecies' range.
- The Endangered Species Act (ESA) covers species and their subsequent subspecies. Why? Because subspecies don't differ that much from each other to warrant distinction in protection.
- There is no "wrong wolf" in the United States. Different subspecies are not different enough to merit complaint, just ask any scientist. At this point, you are just nitpicking.
"THe Wrong Wolf"
Another extremely prominent belief in the western United States is that the wolves in the lower 48 - particularly those released into Yellowstone and other recovery areas in 1995- are the wrong subspecies/ species of wolf. The claim is that a larger, more aggressive, more destructive Canadian wolf (known formally as the subspecies Canis lupus occidentalis) was turned loose into the United States. This Canadian subspecies, it is claimed, is an invasive subspecies. Therefore, the wolves in the lower 48 do not belong here and should not be protected by the ESA or harvest regulations. I'm going to break down this myth, but hold on, because it's a little more than complicated.
Taxonomy 101
Taxonomy is the branch of biology that sorts living organisms based on their relatives. Taxonomy is how scientists categorize a wolf as a dog, a rabbit as a rodent, and a perch as a fish. The broadest category of taxonomy are kingdoms (there are only three: Eukaryota, Bacteria, and Archaebacteria), then get more specific until a species is reached. Binomial nomenclature, or the scientific name of species, uses the Genus and the Species. For example, the scientific name for all gray wolves is Canis lupus. From there, subspecies may be assigned; for example, Canis lupus occidentalis (McKenzie Valley/ Canadian wolf), Canis lupus arctos (Arctic wolf).
How do You determine subspecies?
A subspecies is usually defined as two (or more) members of a species with morphological distinctions (physical distinctions, or habitat distinctions). Often, it's geographically based. For example, tigers (Panthera tigris) have two recognized subspecies: Panthera tigris tigris and Panthera tigris sondaica. These subspecies are based off of morphological differences between mainland and island tigers, respectively (the exception is the Malayan tiger, which is critically endangered on the Malay islands but is tigris tigris). But within these subspecies, there are further classifications - not labeled in taxonomy, because it ends after subspecies- based off geography. The two most known of those further classifications is the Bengal tiger (from India) and the Siberian tiger (Siberia and Eastern China).
An important qualifier of a subspecies is that members of different subspecies can successfully reproduce without consequence to either of their populations. For example, a Bengal tiger and a Siberian tiger could produce viable offspring that is not very genetically unique from either of their ancestors. But a Bengal tiger and a lion could not produce viable offspring; even if the liger hybrid wasn't sterile and could further breed, the distinctions between the original tiger and lion parents are so big that the offspring would be genetically useless to both populations.
In essence: a subspecies is simply a geographic variant based off phenotypic (physical) distinctions.
An important qualifier of a subspecies is that members of different subspecies can successfully reproduce without consequence to either of their populations. For example, a Bengal tiger and a Siberian tiger could produce viable offspring that is not very genetically unique from either of their ancestors. But a Bengal tiger and a lion could not produce viable offspring; even if the liger hybrid wasn't sterile and could further breed, the distinctions between the original tiger and lion parents are so big that the offspring would be genetically useless to both populations.
In essence: a subspecies is simply a geographic variant based off phenotypic (physical) distinctions.
Wolf Taxonomy: It's hard
There's a reason there's been so much debate about the subspecies and relatedness of American wolves- it's ludicrously hard to define. Maybe you think you can divide wolf subspecies by size- for example, the Canadian wolves are "bigger" than American wolves, and are thus a completely different subspecies. But there's always overlap- a Canadian wolf might be small, and an American wolf might be abnormally big. Size is not the determination of a subspecies, because size of subspecies is most often correlated with location. More on that in a second. For now, here's the basic classification of the Canis genus:
Here, subspecies are not listed. Is this because subspecies are not important? Yes and no. For genetics, reproduction, and behavior, no, subspecies do not really matter. Like I said, subspecies can breed without consequence to their subsequent populations. For location and some physical characteristics and behavior - namely food source- subspecies do matter. A side note, the red wolf (Canis rufus) is erroneously left out of this family tree (science term: phylogenetic tree), but they were just recently determined to be a unique species.
Another issue with wolf taxonomy: wolves cover such a huge range historically and modernly, they will likely look different from one another and eat different things, based on the availability of food in their subsequent habitat. Then, of course, there is interbreeding with wolves of different geographies- wolves disperse LONG distances- and even with coyotes (Canis latrans). Since coyotes and wolves are different species, they cannot breed without negatively affecting the success of their subsequent populations, even though coywolves can produce viable offspring. Most scientists believe that coyotes and wolves only started interbreeding when/after wolves were being decimated, since wolves were having a more and more difficult time finding a viable partner. |
North American Wolf Historic History
A note about natural history: not only is it difficult to determine the historic species or subspecies of animals scientifically, but it's also difficult because historical accounts are not the most accurate of sources. There have been many, many publications on wolf taxonomy because of this. For my discussion, I will be using the most recent available information from scientific, peer-reviewed genomic and morphological study.
In the 1700s, during European colonization, there were both gray wolves (Canis lupus), eastern wolves (Canis lyacon), and red wolves (Canis rufus) present. Gray wolves could further be broken down into C.l. nubilus (the Great Plains/buffalo wolf), C.l. baileyi (Mexican gray wolf), C.l. irremotus (Northern Rocky Mountain wolf), C.l. youngi (Souther Rocky Mountain wolf), and C.l. occidentalis (McKenzie Valley wolf). The primary subspecies were nubilus, baileyi, occidentalis, and lyacon.
In the 1700s, during European colonization, there were both gray wolves (Canis lupus), eastern wolves (Canis lyacon), and red wolves (Canis rufus) present. Gray wolves could further be broken down into C.l. nubilus (the Great Plains/buffalo wolf), C.l. baileyi (Mexican gray wolf), C.l. irremotus (Northern Rocky Mountain wolf), C.l. youngi (Souther Rocky Mountain wolf), and C.l. occidentalis (McKenzie Valley wolf). The primary subspecies were nubilus, baileyi, occidentalis, and lyacon.
These were the subspecies that would have been encountered by European settlers. Note that occidentalis had already spread to parts of the lower 48. The red wolf (Canis rufus) would have been located in that white, unfilled area in the southeast United States. Recently, C.l. lyacon has been determined to be its own species, C. lyacon, (naturally, this is still under debate), but in this map it is included in the Canis lupus.
As settlers moved westward and brought their killing with them, the wolf subspecies would have been pushed together, mixing their genes. This is likely how irremotus and youngi came about: "...scientists have found that gene flow can, on occasion, occur between those populations. In other words, even when two populations have some degree of isolation, hybridization occasionally occurs" (Evaluating the Taxonomic Status of the Mexican Gray Wolf and the Red Wolf, 2019). But, there's really no way of telling for sure. Some scientists disagree that irremotus and youngi are distinct enough to have been been considered subspecies in the first place, that they're simply variants of occidentalis or nubilus that came about by admixture.
As settlers moved westward and brought their killing with them, the wolf subspecies would have been pushed together, mixing their genes. This is likely how irremotus and youngi came about: "...scientists have found that gene flow can, on occasion, occur between those populations. In other words, even when two populations have some degree of isolation, hybridization occasionally occurs" (Evaluating the Taxonomic Status of the Mexican Gray Wolf and the Red Wolf, 2019). But, there's really no way of telling for sure. Some scientists disagree that irremotus and youngi are distinct enough to have been been considered subspecies in the first place, that they're simply variants of occidentalis or nubilus that came about by admixture.
“The name Canis lupus irremotus is dated and no longer considered scientifically valid. It is now considered part of the subspecies Canis lupus nubilus, which includes wolves formerly present in the U.S. Great Plains and most of the western U.S. and currently still present in northeastern Canada." - Gary Wiles, wolf expert for Washington Fish and Wildlife
Canis nubilus was thought to have gone extinct by the 1920s. Then, studies popped up showing that the wolves of the Great Lakes- those handful that survived extirpation- are descendants of the buffalo wolf. But are they the same? Have they interbred with occidentalis or lyacon to become their own subspecies? Or are they truly nubilus? Is Canis lyacon truly its own species of wolf, or is it a result of coyote and red wolf hybridization, as well as hybridization with occidentalis? The answer? Nobody agrees on a finite answer.
See? Wolf genetics are complicated.
See? Wolf genetics are complicated.
Gray Wolves Now
Today, three species of wolf exist in the lower 48: Canis lupus (gray wolf), Canis rufus (red wolf), and Canis lyacon (eastern wolf/ timber wolf- the debate is up for this one). The following subspecies of Canis lupus in the lower 48 are generally recognized by scientists:
- Canis lupus occidentalis
- Canis lupus nubilus
- Canis lupus baiyeli
"C. l. nubilus and Canis lupus occidentalis are the most geographically widespread of the five subspecies of gray wolf recognized by Nowak (1995), and share long and complex borders. They also have the largest synonymies of the five species, with 11 synonyms recognized for C. l. nubilus and 6 for C. l. occidentalis...The overlap with mainland subspecies (C. l. nubilus and C. l. occidentalis) is not minimal" (S.M Chambers et al 2016).
What's the difference between these Wolves?
First, let's look at some photos. Can you guess which one is occidentalis, nubilus, or baiyeli?
Even I can barely tell the difference. By geography, the wolf lying in the green grass is from Washington (and thus Canis lupus occidentalis). The standing wolf is from Idaho (and thus Canis lupus occidentalis). The running wolf is from Minnesota (and thus Canis lupus nubilus.... or Canis lyacon, depending on who you ask). The two lounging wolves are Mexican gray wolves (Canis lupus baileyi). Like I said, subspecies are ludicrously similar. But here's some more detail on the most nitpicky of differences.
Canis lupus occidentalis- Mackenzie Valley- aka "the big Canadian wolf that's invasive
Canis lupus occidentalis- Mackenzie Valley- aka "the big Canadian wolf that's invasive
- Said to be the last subspecies to have crossed over into North America and displaced Canis nubilus over time (by the way- displacing is not the same thing as invasive, nor is it an unnatural phenomenon) (SM Chambers et. al 2012).
- Average weight: 80-140 pounds
- Some scientists think that there are two ecotypes of occidentalis (an ecotype is yet another division, this time of a subspecies, that is explicitly based on geography and/or ecosystem): mountain and Pacific, but they're all the same subspecies.
- Found only in genetic remnants of Great Lakes wolves, but enough to consider them the same subspecies. However, it's unlikely the Great Lakes nubilus are the same as the historic Great Plains/ buffalo wolves due to extirpation and subsequent hybridization.
- Average weight: 90-150 pounds (see, same as the Mackenzie Valley)
- The biggest difference between nubilus and Canis lyacon is that lyacon usually has some sort of coyote admixture to it, but nubilus does not.
- Likely the first modern wolf subspecies to develop in North America.
- Average weight: 50-85 pounds
- Scientists agree that the genetics of baiyeli are very much related to lyacon and also to nubilus.
And then... the other wolf species
Canis lyacon (aka the Eastern wolf/ timber wolf) and Canis rufus (red wolf) are two other species (not subspecies) of wolves. You can tell right off the bat that they're different from gray wolves just by looking at them. If you think they look a bit like coyotes, that's because both of these species probably interbred with coyotes at some point, mostly due to wolf extermination.
There's still debate as to what Canis lyacon is. Is it a subspecies? Is it a hybrid? Is it a species? There used to be a debate about whether or not red wolves were hybrids or their own distinct species- this was important because the ESA does not protect hybrids. But a 2019 study has shown that red wolves are, in fact, their own distinct species. There are currently fewer than 20 red wolves in the wild, in coastal North Carolina. The other 200 or so are in captive breeding programs. |
BergmanN's rule
Bergann's rule is a principle of ecology that basically states: animals in colder climates will be bigger than those in warm climates. This rule is much better followed by large animals- like wolves.
Why is this important? Because this means that, hypothetically, if Mackenzie Valley wolves were distinctly larger than their southern cousins (they aren't), their dispersal and introduction into more southern areas would dictate an eventual morphological and behavioral change to adjust to a more southern latitude. Basically, Bergmann's Rule shows that the reintroduced wolves are not messing up the ecosystem.
What Does the ENdangered Species Act (ESA) Say About Subspecies?
According to the ESA, what warrants protection for a species includes “any subspecies of fish or wildlife or plants, and any distinct population segment of any species or vertebrate fish or wildlife which interbreeds when mature" (ESA). So legally, all subspecies of gray wolves are covered under the ESA (whenever they're listed, that is).
Conclusively...
The wolves in the lower 48 United States belong here. They are not invasive, destructive, or more aggressive killers than other subspecies. The definitions of species and subspecies are convoluted, complicated, and made even more so by the uncertainties of historic populations. But whatever the case... whether you like it or not, the lower 48 is the historic home of these wolves. And they're here to stay.
Header image: Niko Pekonen (@npekonen on Instagram)