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Posts Tagged ‘wolves’

atila and the wolf

Photo by Tanja Askani.

In paleontology, a group of scholars exists largely on the fringe of the discipline. No matter what evidence is provided, they find some way to pump out a paper that says that birds cannot be dinosaurs. An established scholar or two will the publish and beat them down, but there is still an idea in the public mind that there is a debate between dinosaur experts about whether birds are a specific type of theropod dinosaur.

These scholars are known as BAND (“birds are not dinosaurs”), and they do get the attention of the popular press, even if ignored by the mainstream scholarship.

I’ve noticed in that in all my years writing about dogs and their taxonomy that there is a similar group in this sphere as well.  The difference is this group had the backing of one of the leading authorities on dogs in the world, Raymond Coppinger.

Coppinger was certain that dogs had to be classified as Canis familiaris, based upon a very crude ecological species concept. Village dogs that scavenge off human civilization hold a different niche than pack-hunting wolves, ergo, they are different species. Never mind that if we applied that same standard strictly, Arabian wolves, which scavenge a lot and don’t often hunt large prey, would be a different species from arctic wolves or any of the moose, elk, or bison-hunting wolves we have in North America.

If we are to adhere to cladistic classification, though, it is virtually impossible to create arbitrary species for dogs. The reason is best summed up in this paper that compared genomes of many wolves and a few dogs that have origins on different continents. The authors concluded:

 [W]ithin the Old World clade, wolf and dog represent sister taxa. Therefore, suggestions that the dog or dingo are a separate species (Canis familiaris) (e.g., Crowther et al. 2014) would cause gray wolves to be a polyphetic taxon; and consequently, our results support dogs as a divergent subspecies of the wolf. This result has societal significance as legislation in some countries and regional governments consider wolves and dogs as distinct species restricting the possession, interbreeding, or the use of vaccines and medications in wolves or dog–wolf hybrids if they have only been approved for use in dogs. In this sense, analysis of evolutionary history informs law and veterinary practice, as dog lineages are nearly as distinct from one another as wolves are from dogs, and the justification for treating dogs and wolves differently is questionable.

That pretty much should end this discussion. What these authors found and has been discovered in other papers is that dogs descend from a ghost population of gray wolves, Eurasian gray wolves, to be exact.

Lots of other experts agree with this assessment. Darcy Morey, an archaeologist with a great expertise in the study of Pleistocene wolves and early domestic dogs, has the address for his website as “dogsarewolves.com.” He and Rujana Jeger have formulated a conceptual framework of dog domestication that is quite unique. Basing their model upon trophic strategies on behalf of the wolves and shifting perceptions of humans, the authors contend that wolves that became dogs attached themselves to people. These early humans were often already acting as the apex predators in the ecosystem of the Pleistocene, and the wolves that did join up with people were able to take advantage of this niche.  Pleistocene wolves were not operating as apex predators in a faunal guild that included machairiodonts, cave lions, cave bears, and Pleistocene spotted hyenas, but when those animals became extinct, the wild wolves became the apex predators of Eurasia.  The wolves that hooked up to people joined humanity in agricultural societies and joined us as apex consumers. When humans began to domesticate other livestock,  wild wolves were seen as competitors and killed off.

The idea that dogs are not wolves does have some currency, especially if you’re quite stuck on Southeast Asian origins for domestic dogs. Vladimir Dinets believes that wild Canis familiaris was some kind tropical Southeast Asian canid that was related to but not descended from Canis lupus.  There is still a massive debate as to where dogs originated, and it should be noted that there are as many good papers that have concluded European or Central Asian origins as have suggested as Southeast Asian origins.

The reason you would go for wild Canis familiaris in Southeast Asia as the ancestor is that Southeast Asia is one of the few places in Eurasia that never has had gray wolves living there. In these schools of thought, much emphasis is placed upon Canis variabilis a possibly being the wild ancestor. Of course, Canis variabilis disappeared from the fossil record 300,000 years ago, and no serious scholar thinks dogs diverged from wolves that early.

The real problem is the genetic closeness between wolves and dogs, and that same genome comparison study mentioned earlier shows a significant gene flow between wolves and domestic dogs. Up to a quarter of all Eurasian wolf genomes likely have some dog ancestry, and in East Asian wolves, the dog component of their genome can be as high as 20 percent. In European and Middle Eastern wolves, the dog component can be as high as 25 percent.

The only thing that keeps dogs from swamping the Eurasian gray wolf population with dog genes is the reproductive and territorial behavior of wolves. Wolves generally allow only one female to raise her pups. Wolves generally kill dogs that wander onto their territories, and they will kill dogs that are in territories they wish to claim.

But dog genes are getting into the wolf population at pretty high rate in Eurasia, a much higher rate than you would think of for two distinct species.

A lot of the people who have a hard time recognizing dogs as wolves are tired of bad dog training advice that is based upon bad wolf science.  They might also be tired of claims from the raw feeding community that say we must feed dogs like wolves.

But just because people misuse the classification does not infer that the classification is wrong.

Cladistically and genetically, dogs represent a now extinct population of Eurasian gray  wolves.  If these terms mean anything, then dogs are Canis lupus familiaris.

These theorists are always going to have a reason to say that dogs are not wolves, just like the BAND theorists.  Indeed, it may be necessary to refer to them as DANW (Dan-double u), for they are they are coming up with reasons to avoid classifying dogs as wolves, no matter how much genetic or archaeological evidence is presented.

In the grand scheme of things, classifying dogs has little effect on our practical understanding of them, but this continuous phylogeny denial makes the dog world seem oddly out of step.

No one would miss a beat if you called a Hereford a domesticated aurochs.  A pekin duck a domesticated mallard? No problem.

But if you say dogs are wolves, which they clearly are, then you’re anti-science.

I’m not, though. You’re the one rejecting cladistics for your special classification model.

I’m adhering to the same model that would be accepted with any domestic species and its wild ancestor.

You’re just rejecting it because you think that’s what the science says. Maybe, but it’s hard to argue with DNA.

But they do it on Maury Povich every day, so why not?

Update: A more recent study that examined the genomes of gray wolves from across their range revealed that 62 percent of all Eurasian wolves have some dog ancestry. That’s much higher than the genome comparison study mentioned above. 

 

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I’m so glad these taxonomy issues are being raised on a popular science Youtube series:

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This is “Mr. Ethiopian wolf,” pretty much the world’s leading expert on the species:

There is a very interesting discussion in the Q and A portion about the introgression of dog genes into Ethiopian wolves and why that’s not necessarily always a bad thing.

The current research is working toward a full genome sequence of the Ethiopian wolf, and if they are like coyotes and “Holarctic” wolves, I bet there will be some surprises in store.

 

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dire wolf mesomelas

Yep. This was an April Fools’ prank.

That’s okay. I had one pulled on me last night at the cabin where we were fishing. About 10 o’clock last night, my dad shouts “Oh my God! There is a bear in the trash!”

By the time everyone had rushed to the windows to see– and I had just been roused from slumber– it was soon revealed there was no bear.

Yes, and just as there was no bear, all that was in the post about the dire wolf’s genome being closely allied to black-backed jackals is utter nonsense.

But I have always imagined that this was a possibility, because I think our assumption that dire wolves were very closely related to modern wolves really hasn’t been tested out empirically.  We have some phylogenetic trees drawn from paleontological analysis, but one must be very careful of these studies. Parallel evolution is a very common occurrence in canids, and I’ve come to the conclusion that everything one reads about paleontology and canids needs to be taken with a grain of salt.

So yes, it’s an April Fool, but it is a definite possibility.

Oh, and please don’t hate on my dodgy “photoshop.”

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coyote profile pic

I am a coyote lover. No two ways about it.  I have always been interested in wolves and dogs, but in the past couple of years, I’ve had encounters with Eastern coyotes.  And they are every bit as fascinating. Western man has thrown every single weapon he could contrive at them, and all they have done is spread all over the continent.

So it was with great joy when I got a chance to read Dan Flores’s  Coyote America. I had heard the author interviewed on Steven Rinella’s podcast a while back, and I was really fascinated about what he had to say about Pleistocene megafauna on the North American Great Plains.

I also knew he was writing a book on coyotes, and I wanted get his take on them.

I’ve just started reading the book. I really enjoy his discussion about Native American traditions with coyotes. I am a damned, no-good Easterner, so I know very little about those traditions.

But I do have a quibble. It’s a friendly quibble. In one part of the book he describes coyotes as being as genetically distinct from wolves as humans are from orangutans and that the two species split from a common ancestor some 3.2 million years ago. He uses a lot of the paleontological data from Xiaoming Wang, who is a great canid paleontologist, who posits that coyotes evolved from directly from Canis lepophagus and that they are wholly a North American lineage.

Now, this is paleontology, and it’s not exactly the best way to determine evolution relationships between very closely related canid species. The reason why is that canids have a tendency toward parallel evolution. For example, the bush dog of South America has dentition that is very much like the African wild dog and the dhole, and at one time, it was suggested that the bush dog was actually a species of dwarf dhole. We now know from genetic studies that it is actually a close relative the of the maned wolf, and it is well-nested in the South American canid clade.

It is definitely true that coyotes resemble African golden jackals, but similarities in appearance have led to error here.  Molecular geneticist have recently found that African golden jackal is actually much more closely related to coyotes and wolves than it is to the Eurasian golden jackal. That means that two animals we thought were the same species actually turned out to be two.

And when it comes to the relationship between coyotes and wolves, molecular geneticists had long assumed that the two species split around 1 million years ago.  In countless dog domestication articles, the molecular clock has been calibrated around a 1-million-year-old split between wolves and coyotes. I have always thought that was weird, because the paleontology studies suggested a much older divergence.

Well, a recent comparison of wolf and coyote genomes from across North America revealed that the actual separation time was something more like 50,000 years ago. That means the animals we’re calling coyotes now aren’t the same thing as those million-year-old fossils.  Those animals are of evolutionary dead-ends that just happened to have a very similar morphology to a coyote in much the same way that African and Eurasian jackals do. Of course, we cannot get genetic data from such old fossils, but it could be that some of these dead-end canids might be more closely related to black-backed and side-striped jackals, which really did diverge from the rest of Canis a really long time ago. They are more divergent from the rest of Canis than the African wild dog and dhole are, and the dhole and African wild dog have their own genera.

If coyotes and wolves diverged only 50,000 years ago, then this raises an interesting taxonomic question. All extant wolf lineages diverged in the past 44,400-45,900 years, as a recent study comparing wolf genomes revealed.  These means the genetic difference between a wolf and a coyote is not much more than the greatest genetic variance between wolves. (Generation time are roughly similar in both wolves and coyotes).

This means that the creatures we’re calling coyotes now actually derived from the Eurasian wolf. The reason this animal looks so much like a jackal isn’t because it represents a primitive North American Canis lineage, but because the larger, pack hunting wolf from Eurasia couldn’t live very well at middle latitudes in North America. At the time, dire wolves were occupying this niche. There were also dholes coming into North America, which means that the pack-hunting wolf of Eurasia really had some strong competition. That means that these wolves evolved more toward the generalist jackal body-type and ecological niche. They did so in parallel to the Eurasian and African jackals.

This is very similar to what happened to the first radiation of Eurasian lynx into North America. Eurasian lynx are pretty large, weighing as much as 70 pounds, but they found the mid-sized cat niche already locked up in North America. So they evolved into the smaller bobcat. It just happened millions of years before the wolves that became coyotes came into the continent.

The fact that wolves and coyotes are this closely related and have exchanged genes so much across the continent raises some important questions about what a coyote is. The comparative genome study on wolves and coyotes showed that the animals called the Eastern wolf and the red wolf, which Flores considers valid species in the book, are actually hybrids between wolves and coyotes. I’ve long been a skeptic of the red and Eastern wolf paradigm, but this study actually makes me question coyotes.

One could actually argue that coyotes are a subspecies of wolf. This is a controversial thing to say, but it was once controversial to say that dogs and wolves were the same species– and now there is growing acceptance (at least among scientists) of this fact.

It is certainly true that all wolves, jackals, African wild dogs, and dholes do descend from a coyote-like North American ancestor.  But to assume that coyotes are directly derived from this ancestor is a major error, and one that has been falsified in the molecular studies.

If my interpretation of the genetic studies is correct, the coyote should be called the “thriving wolf.” Unlike the bigger ones, it was able to survive all that we threw at it. The more we persecuted it, the greater its numbers became, as did the vastness of its range. It is an adaptable, resourceful survivor, and that makes it the perfect “American avatar” to use Flores’s construction.

So that is what a coyote is.  It is the wolf that thrives.

 

 

 

 

 

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Arctic hare vs. wolves

Quite a chase!

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brush wolf

It cannot be overstated how much the discovery that coyotes are not as distantly related to wolves as we believed ultimately questions our entire understanding of the evolution of the Canis species.

The traditional understanding Canis species evolved from some form of Eucyon dog some six million years ago. Wang and Tedford, who wrote the most important book on the paleontology of the dog family, believe this was Eucyon davisi, which was the first of its genus to enter Eurasia. The genus Eucyon is where the common ancestor of the Canis dogs (including Lycaon and Cuon) and the South American wild dogs would be located. Eucyon dogs were small. Imagine them as being something like a black-backed jackal or a Hoary fox rather than a coyote.

Then, 5 million years later in the Southwestern US and northern Mexico, a coyote-like Canis evolved, which was called Canis lepophagus. This animal is sometimes considered the common ancestor of wolves and coyotes. It may be, but considering how close we now know wolves and coyotes are now, it’s not the most recent common ancestor. Canis lepophagus did migrate into Eurasia, where it either founded or is identical to Canis arnensis.

In Eurasia, several smaller jackal-to-coyote forms evolved. One of these was Canis estruscus,  which then evolved into Canis mosbachensis (which is called Canis variabilis in China).

Ron Nowak believed the red wolf was an offshoot of this wolf that wound up colonizing North America and then becoming isolated from the rest of Canis mobachensis when the ice sheets expanded. There was also a competing view that the red wolf was actually a remnant version of Canis edwardii or Canis priscolatrans (which were probably the same animal). This animal was roughly the size of a red wolf, but Nowak rejected it as a red wolf ancestor because it lived too early for what he thought were red wolf fossils.

The Eurasian wolf species evolved mosbachensis-variabilis, but the two forms of wolf shared habitat and likely exchanged genes, making it very difficult

The coyote’s evolution was never clear. It was thought to have evolved out of Canis lepophagus. It was thought that lepophagus evolved into edwardii, and then it began to become more gracile and smaller, eventually becoming the now coyote.  It’s now pretty clear that it evolved out of the Eurasian Canis lupus and not these endemic North American “wolves.”

It either evolved from the modern wolf, which evolved into roughly its current form 800,000 years ago, or it came from a late surviving mosbachensis-type wolves that were regularly crossing with modern wolves before they came into this continent. Maybe the remains that Nowak had been considering “red wolves,” were actually these ancestral wolves that were evolving into the modern coyote.

Maybe when this wave of wolves came back across from Eurasia, perhaps 50,000-100,000 years ago, it came into a world already dominated by a dire wolves, which already occupied the niche for large, pack hunting canids and this wave of Canis lupus evolved as the American jackal.  After all, the bobcat is just a diminutive Eurasian lynx that found itself in a very similar position when it came into this continent, and it evolved to be a smaller animal that generally hunts smaller quarry than its larger ancestor. Of course, the modern bobcat didn’t reach its current form until about 20,000 years ago, but it still was forced to adapt to a slightly different niche than its Eurasian ancestor.

In literature on the paleontology of Canis, there is a heated debate as to how these animals all fit. The conventional view is that the wolf evolved from Canis mosbachensis/variabilis through Canis etruscus, which may be the same thing as Canis edwardii/ Canis priscolatrans. Wang and Tedford contend that the coyote and wolf split from Eucyon.  The modern wolf evolved from Canis chihliensis, which was a large wolf-like canid. It spread into North America to found Canis armbrusteri, which then evolved into the dire wolf (Canis dirus) in North America and Canis gezi and Canis nehringi in South America.  In the Old World, another offshoot of chihliensis gave rise to Canis falconeri, which the supposedly gave rise to the Xencyon, which is supposed ancestor of the dhole and African wild dog. Another view holds that the Armbruster’s wolf (C armbrusteri) is descended from edwardii/priscolatrans (which may be the same as etruscus). This lineage then gave rise to the dire wolf and the two sister species in South America, thus descending solely from North America wolves.

All of these ideas come from paleontology, and they pretty much are done without looking very deeply into the studies that are examining the DNA of these species. It is pretty obvious from that literature that the notion that coyotes and wolves split at the time of the Eucyon ancestor is quite wrong. For that hypothesis to work, African of  wild dogs and dholes would have to be genetically closer to wolves than coyotes and golden jackals are. They aren’t.

But if the genome-wide analysis shows that coyotes are so much more closely related to wolves is true, then all these fossil and subfossil canids that are said to be the most recent common ancestor of wolves and coyotes simply aren’t.  Instead, all of these species that are classified in Canis are likely a mix of evolutionary dead ends, like the dire and Armbruster’s wolf, or could be hidden ancestors of extant canids that aren’t wolves or coyotes.

For example, black-backed and side-striped jackals diverged from the rest of Canis and its allies at about the same time that Eucyon was diverging from Canis. It is possible that there are many relatives of these particular dogs that are hidden in this vast sea of Canis fossils.

The new discovery about the coyote’s split from the wolf also means that any remains of North American canid that are listed as coyote that date to 1 million years before present are not coyotes. What they actually were is a very good question.

We’ve spent a lot of time assuming that coyotes and wolves were quite divergent. We know now that they really aren’t, but when we look into the past at all the “wolves” and “coyotes” that came before, we see how this genus became so successful. It can easily evolve into big game-hunting forms, but the real success is in its ability to assume the size and shape of the generalist predator. Phenotypic plasticity is a wonderful thing for a lineage to possess.

But the real message of the new discovery about wolves and coyotes should be is a cautionary tale about paleontology. Paleontology is a wonderful science, and it makes amazing discoveries every day, but when its faced with a lineage of animals where phenotypic plasticity and tendencies toward parallel and convergent evolution are commonplace, it is bound to make errors. Paleontologists aren’t examining flesh and blood that can have its molecules tested for relationships. They are measuring anatomical characters and determining phylogenetic relationships based upon the similarities of these characters.

Which works well.

Until you get something like wolves and coyotes, where there are many ancient fossil and subfossil remains that look like they could be ancestors of either.

But the DNA says they aren’t.

And paleontology would have problem catching the inverse. There are many species that we’ve discovered only through DNA testing. African butterfly fish in the Congo and Niger basins look identical to each other, but they have been isolated from each other for 57 million years. I have yet to see this species split into two, but if they were mammals, you could bet they would be placed in distinct species in heartbeat.

Paleontology is missing some really important things we’ve since found out through molecular analyses.

And paleontologists know this.

They are working with the data they have, and by definition, it’s going to be more incomplete than genetic studies.

Science is provisional. Different disciplines and methodologies are going to come up with different answers. It’s pretty amazing that one genome-wide assay study can wipe out so much literature in paleontology.

These debates have been raging for years.

And it turns out that everyone was actually wrong.

Update 21 August 2016:  It turns out that I missed a paper that actually did some limited DNA analysis and found that Canis nehringi was pretty much a South American dire wolf, as in it was likely the same species as the North American dire wolf. Canis gezi, however, was  more closely related to the modern maned wolf and had been incorrectly identified as a wolf. So let this stand as a correction to the error above.

 

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