Archive for the ‘wild dogs’ Category

In recent post I wrote about the new research regarding the thylacine’s size, I mentioned that maned wolves might violated the “costs of carnivory” rule, which states that predatory mammals that weigh more than 21 kilograms (46 pounds) must haunt larger prey sources to survive.

Maned wolves do exceed this size, but their diet does not consist of large prey. They are not a threat to ungulate livestock. They take only small prey, such as rabbits, rodents, and small birds. They could be a threat to chickens and other poultry, but they aren’t cattle killers.

On a superficial reading of their ecology and diet, one would assume they would break this 21 kilogram rule. The largest ones do get to around 23 kilograms, and if they are that large, then they surely break this “costs of carnivory” rule.

But they don’t.

The reason is they have a most unusual diet for a canid.  Between 40 and 90 percent of their diet can consist of a single fruit called a lobeira or “wolf apple.” The average diet of a maned wolf is around 50 percent vegetable matter, which means they aren’t as bound by the rules of carnivorous diets as other mammalian predators are.

The maned wolf first appeared in the fossil record in what is today the Desert Southwest what is called the Blancan faunal age (late Pilocene to early Pleistocene).

It entered South America, along with a whole host of other canids, and it evolved to a specialist niche as a grassland predator. Many species of similar-sized dog were also diversifying in South America, it is likely that it evolved its unusual diet as a way of avoiding competition with more carnivorous canids.

So vegetarian are maned wolves that when fed a typical wild carnivoran diet in zoos, they often develop bladder stones. Their kidneys cannot absorb a particular amino acid called cystine, and the excess cystine turns into stones.

Most mid-sized canids are true generalists in their diets. The exceptions are the maned and Ethiopian wolves. The Ethiopian wolf runs between 14-19 kilograms, so its rodent specialized diet does not violate the rule.

But the maned wolf’s heavily frugivorous almost takes them out of the predator guild entirely.  They are as almost omnivorous as most bears are, and all extant bear species exceed 21 kilograms at maturity.

So maned wolves don’t violate the costs of carnivory rule. They do so, because they are far less predatory than virtually any other dog species. They are certainly less predatory that other dogs of their size.


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red wolf

I don’t know a damned thing about football. I have hated it my whole life.  I cannot carry on a halfway decent conversation about it. Taking me to a football game for me to enjoy it is about like taking a dog to the Louvre and expecting him to appreciate the art*, and I will remain happily ignorant about the subject until my dying day.

Currently, the US is going through some great historical reckonings about racism, which I must admit that I do fully support.  There is a lot of controversy about taking down statues and renaming streets, and it’s all horrendously gut-wrenching and difficult.

Among the changes that is happening is that the professional football team in Washington, D.C. is getting its name changed. For decades, various groups affiliated with various Native American organizations have been trying to get the name changed. It has been called the Redskins, and as someone who doesn’t care about football, I think it’s kind of silly that we have a name like this for anything.

But all the recent events have finally led to decision to change the football team’s name.

And although we don’t know the new name. The current favorite is “Redwolves.”

Well, that’s a different controversy!

And no, I’m not saying the systematic racism and oppression of Native Americans is an any way comparable to a big taxonomy kerfuffle, but it is controversial.

As long time readers of this blog know, I generally reject the “red wolf” paradigm. I base this rejection upon really good genome-wide analysis. I also reject the ancient North America-only origins for the coyote, and I believe that both the red wolf and coyote are offshoots of the Eurasian gray wolf.  Indeed, I have proposed that the coyote is a form of gray wolf in the same way the domestic dog is , and that it should be recognized as Canis lupus latrans.  The red wolf is a hybrid between relict gray wolves that lived in Louisiana and Texas and the coyote.

One unusual discovery about gray wolves, coyotes, and “red wolves” is that all three populations are about as genetically distinct from each other as humans from different continents are.

And this discovery might tell us thing or two about racism in our own species. At one time, the various races of humanity were often classified into different species. Some people resisted this notion, which popular in the nineteenth century.

However, among them was the Rev.  John Bachman, a Southern Lutheran pastor, who also ministered to the slaves. He defended the institution of slavery, of course, but he did not think that African Americans were a different species from Europeans.

Bachman also believed the wolves of North America represented one species, and this idea was very much expounded in Aubudon’s The Viviparous Quadrupeds of North America. Bachman and Audubon worked closely on the text, and although Bachman and Audubon are credited with documenting the red wolf as a species, they were very clear that were the same species:

“The Wolves present so many shades of colour that we have not ventured to regard this [the red wolf] as a distinct species;  more especially because it breeds with those of other colours, gangs of wolves being seen in which this variety is mixed up both the grey and the black” (243).

Bachman and Audubon’s initial idea that the “red wolf” was just a color phase has since been revealed in the genome-wide analysis of wolves, coyotes, and red wolves are so closely related to each other that it would almost make sense to classify them as one really diverse species. Bachman and Audubon were certain that the coyote was a very distinct species, but it likely diverged from the gray wolf within the past 50,000 years. And a gene flow still exists between coyotes and gray wolves across the continent.

Humanity is so caught up in labeling, and now, we’re trying to undo some of the damages that were done through our pseudoscientific labeling in the past.

And Confronting past and present racial discrimination is the current zeitgeist.

I reject racism very clearly and definitely. I don’t want to have teams with racist names or have statues of Confederate generals on public property.

I am what some people would call “left wing scum.” I wear the badge with pride.

But I wonder if much of my rejection of Canis rufus is also my rejection of racism. I think the evidence is strong that the species should not be considered valid, but I wonder if my strong aversion to the classification of this species is part of my deep anti-racist ideology.

Maybe it clouds how I view data.  Ideology does drive a lot of scientific understanding. Philosophy underpins so much more than we’re ever willing to accept.

I know that I have intellectually made the case to myself.  It makes me look like I hate endangered species to some poor readers out there.  Or that I want some sort of whole-scale blood letting among the red wolves.

But I don’t think that this species was defined correctly. It wasn’t even defined when wolves were commonplace in Texas and Louisiana, and the genetic data that was used to identify them as a species in the 1970s was rather primitive. Indeed, much of their defining characteristics were based upon what they looked like, and as Peter Steinhart pointed out in The Company of Wolves, it was not unusual for 75-pound “red wolves” and 25-pound “coyotes” to appear in the same litter. The founding population of red wolves consisted of only 14 individuals, and when they were released in the Alligator River National Wildlife Refuge, it was assumed they would keep coyotes out and not interbreed with them.

Indeed, what happened was they started interbreeding with Eastern coyotes as those smaller canids began colonizing the red wolf release area.

Believing that coyote blood contaminates red wolf blood has resulted in several litters of pups being euthanized. The coyote cannot sully the blood purity of the red wolf, even when the genome-wide analysis shows that the red wolves are themselves admixtures of of coyote and extinct Southern gray wolf.

We have defined these animals so rigidly before the law that the wolves cannot choose their own mates.  If they pair with a coyote, they have created a mongrel.

It is this level of stupidity that I reject when it comes to nature and simple ethics. These animals cannot be thought of as truly wild and natural if they must be maintained only by keeping the coyotes from mating with them.

It reminds me so much of the racial purity nonsense that was once so prevalent in the United States and still exists, though often is never explained or articulated in this fashion.

And when wildlife management apes this sort of buffoonery, I have to reject it. I am not saying that red wolf advocates are racist, but the way they describe them and the crosses between coyotes and red wolves truly sounds so eerily similar to our antiquated ideas about blood purity that I am instantly repulsed by it.

So yes, let’s rename the football team.  Lets oppose racism in all its forms.

But renaming the team by this name is not without its own controversies. Indeed, it echoes and rhymes so much with the ones facing the human world that one cannot stop and marvel at the folly.


*Stolen from Julie Zickefoose.



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coyote pupps.jpg

I have a lot of quibbles with Dan Flores’s book, Coyote America. Among them is a contention that coyotes howl because it allows them to “take a census.”  If no other coyotes howl back, the females wind up releasing more ova and having larger litters. This description, which Flores calls an “autogenic trait,” cannot be found anywhere in the coyote literature. His account is not described in the book, but it is mentioned in his interview with National Geographic and on The Joe Rogan Experience.

I have no idea where Flores got this idea, but it’s not really what happens. The literature on why coyotes have larger litters in areas where they have been heavily hunted says that the larger litter sizes are associated with better access to food resources. The best-known paper on this issue comes from Eric Gese, a researcher with the USDA, who studied coyote population dynamics in an area of Colorado.

Gese contends that what happens with coyotes in pressured areas is that the surviving females are healthier, simply because they have access to more food resources. This greater health causes them to release more ova during the estrus cycle, and this increase in ova results in greater litter sizes.

It is not because the coyotes are taking census and can somehow magically figure out that they should produce more young.  It is simply that the coyote females’ own bodies respond to greater food resources by becoming more fertile.

What has possibly evolved in coyotes is that they have a tendency to become significantly more fertile when the females are at their most healthy. This is a great trait for a mesopredator to have.

After all, coyotes evolved in North America with dire wolves and a host of large cats breathing down their necks. Natural selection favored those that could reproduce quickly if populations were dropped dramatically.

But it’s not because of some “autogenic trait.” It is simply how coyote populations expand as mesopredators with increased or decreased access to prey.

So yeah, my take on Coyote America is that it is mostly a science fiction book. Not only does he mess up the exact genetic difference between a wolf and a coyote, which is not equivalent to the genetic difference between a human and an orangutan (as he claims),  he also messes up that coyotes really do hunt down and kill cats and eat them. They are not just killing a competitor. They are using cats as a food resource.

This was a book I was so looking forward to reading. It got good press, but the actual science in it was so lacking.


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tibetan fox vs. marmot

The 2019 winner of the London Museum of Natural History’s “Wildlife Photographer of the Year” is Bao Yongqing, who took this amazing predator-prey action shot on the Qinghai-Tibetan Plateau. It shows a Tibetan fox (Vulpes ferrilata) trying to catch a Himalayan marmot (Marmota himalayana).

In an interview with the photographer, it was revealed that the fox was a vixen with young that needed meat. Even after a long stalk on the marmot, the prey was not easily subdued. Other marmots came to its defense, which is something that our groundhogs would never do. The fox had do dive around the defensive marmot to get at its prey, but eventually, the targeted individual collapsed and fell to the fox’s jaws.

Tibetan foxes have only recently become well-known. The initial descriptions of them were based upon pelts, and it is only now that we have a popular concept of these foxes with their oddly-shaped, squared-off heads.

I was surprised that this species of marmot would engage in altruistic behavior. The marmot species I know best, the groundhog (Marmota monax) does not do this. They are way more solitary than those marmot species of Central Asia, though, and this social behavior can be of great benefit for life on the exposed ground.

This is a pretty cool photograph that reminds me of another winner. In 2015, a photograph of a red fox killing and eating an arctic fox in Canada won earned the photographer this same award.

So foxes killing things– well, that’s an award winner these days.

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Isle Royale’s new wolves

isle royal new wolf

The wolf reintroductions that began last year on Isle Royale are starting to bear fruit.. Reports are that two male wolves and a female are running together,and they are beginning to hunt moose calves, snowshoe hares, and beavers.

Further, it was reported today that one the last survivors of the original Isle Royale wolf population was killed in a scuffle with the new wolves.  This male wolf from the original population could be the last survivor, because the other remaining wolf is a ten-year-old female that has never been radio-collared or studied. She could very well be dead by now, but researchers are trying to figure out her whereabouts.

Wolves and moose were not the original predator-prey dynamic of the island.  The original dynamic involved woodland caribou, which became extirpated, and Canada lynx, which became extirpated in the 1930s, and coyotes, which became extirpated shortly after wolves arrived.

The first wolves crossed an ice bridge from the Ontario mainland and colonized the island in 1949. The moose showed up in the early 1900s and came either by swimming or through human stocking.

The original wolves of Isle Royale were a unsustainable population. The ice bridges stopped forming every year to connect the island to the Minnesota and Ontario mainlands, and new genetic material never had a chance to work its way into the population. One wolf, Old Gray Guy, did manage to walk over into the island in 1997, and he did offer some genetic rescue. However, his genes wound up swamping the population, making inbreeding issues worse.

This island, which never was known for having wolves or moose, is now a sort of experiment that is going to be managed through human interference. Every few decades,  wolves will have to be released on the island, just to maintain the population’s genetic diversity.

Isle Royale now exists somewhere between a zoo and a wildlife preserve.  Wolves must be maintained through constant human interference. Moose are controlled by wolf predation. Moose control the growth of trees on the island, and by continuously introducing wolves, the ecosystem is managed.

This is not an attempt to restore an ecosystem to the time of yore, before man began industrial level exploitation of the forests on the island. If it were, then the National Park Service would open up a moose season on the island with hopes of eventually extirpating them. It would restore caribou and turn loose a bunch of Canada lynx and coyotes.

But so much research and public awareness of the island comes from its studies of wolf and moose dynamics that it will be maintained as a wolf and moose park. In this way, it is an artificial wilderness.

But no place affords such easy access to wolf and moose predator-prey population dynamics, so it will be restored to the state it was in the 1950s.  It is an amazing place, and the research tells us so much.

But it is not being left to nature. And it is not a restoration of the original condition. It is an aesthetic that exists beyond our usual concepts of wilderness. We have a place where wolves can hunt moose, and scientists can study them with relative ease.

And that practicality trumps Gaia and probably will every time.




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panama coyote

The coyote has spread to almost the entirety of the North American continent. They are absent from much of the treeless tundra of the Canadian High Arctic, but they are at home in Alaska and Labrador. They range all through the United States and through all of Mexico. They live in every Central American nation and are working their way through Panama.

A recent survey of coyotes and crab-eating foxes in Panama revealed that two species now have an overlapping range. The crab-eating fox (Cerdocyon thous) is widespread in northern South America, but only recently did a few of them wander into Panama.  This survey used a combination of camera trap and road-kill data to get an idea of where both canids live in the country.

Deforestation in Panama has opened up new territory for both species, which do much better in human-dominated environments.  Coyotes now are at the edge of the great forests of Darien. Beyond those forests lies Colombia– and a whole new continent.

Further, coyotes could possibly enter Colombia through a coastal approach, simply crossing onto the beaches of eastern Panama and walking down the coast.

Also, the researchers are noticing that some coyotes have dog-like features, which suggests they are interbreeding with village dogs. The dogs could confer onto the coyotes some advantageous genes that might make colonization of South America easier.

So my guess is it won’t be long before coyotes make it to Colombia, and when they do, they will be the first wild Canis species to enter that continent since the dire wolf.

No, they aren’t as impressive in their forms as that creature was. But they are impressive in how they have thrived despite all humans have thrown at them.

Of course, when Panama was a province of Colombia, Panama was considered part of South America, and if that were still the case, we could already say they colonized the continent.  Many old maps of South America show Panama sticking off upper left of Colombia.

But whatever one thinks, coyotes are very likely to make it into Colombia. They will likely spread from there throughout northern South America. What this means for the native species of South America, we can only conjecture.

But it is going to be an interesting mess.

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xenocyon and cynotherium

Depiction of Xenocyon lycaonoides (in the back) with Cynotherium sardous (in the front).

The “hunting dogs” are sister lineage to the true wolves. They were once widespread across Eurasia, Africa, and into North America. Today, the lineage is survived by two species, the dhole (Cuon alpinus) and the African wild dog or painted dog (Lycaon pictus).

But during the Pleistocene, a third species, much larger than two extant species, was ubiquitous. This species, called Xenocyon lycaonoides, was found all over Africa and all over Eurasia.  It ranged into North America, where its remains have been described as Xenocyon texanus.

It was long accepted in paleontology that the dhole and African wild dog derived from Xenocyon lycaonoides, but new evidence that shows the African wild dog deriving from a Pliocene African species called Lycaon sekowei casts that idea into doubt. Further, because the dhole and African wild dog are so closely related to each other, it is doubtful that either derives from Xenocyon.

My take, based upon simple chronology and the genomic analysis of living species, is that Xenocyon and its offshoots were a sister lineage to that which leads to the dhole and African wild dog.

The best way to think of Xenocyon lycaonoides is that it was the gray wolf before there was a gray wolf. It was a pack-hunting canid that was able to expand its range over a wide range. It was roughly the size of a large northern gray wolf, and it would have been a formidable predator of large game.

On islands, though, Xenocyon evolution went a bit weird. On Java, two descendants of Xenocyon lycaonoides evolved. One was Merriam’s dog (Megacyon merriami). It was even larger than the mainland form, but over time, it was replaced by a smaller form that averaged 22 kg (48.5 pounds) called the Trinil dog (Mececyon trinilensis). A new analysis of these Pleistocene canids places both in the genus Xenocyon (which fits a cladistic classification model) and shows that the smaller Trinil dog derived from the larger Merriam’s dog.  Increased competition from tigers and other large predators forced the larger Merriam’s dog to target smaller prey, and over time, they became smaller.

Anothe even more extreme insular form of Xenocyon evolved on the Pleistocene island of Corsica-Sardinia. This island is now two islands in the Mediterranean, but during the Pleistocene, they were connected to each other. On that Pleistocene island, Xenocyon lycaonoides became isolated on an island that was full of small prey, especially a species endemic pika.  This Corsica-Sardinian canid became a specialist in hunting burrowing prey.  It had the ability to thrust its head out laterally better than any living canid, which would have given it an advantage in catching quick-moving prey that would take refuge in burrow.

This species is called the Sardinian dhole (Cynotherium sardous), but it is not directly related to the modern dhole. It was the size of a golden jackal or a small coyote, and it went extinct after humans colonized Corsica-Sardinia at the very end of the Pleistocene. It was the last of the Xenocyon derivatives to go extinct.

The Mosbach wolf (Canis mosbachensis) was a contemporary of the larger Xenocyon lycaonoides.  It was smaller canid that varied in size from an Eastern coyote to an Indian wolf.  It eventually would evolve into the larger gray wolf, which would have a similar evolutionary trajectory to the Xenocyon. It would spread over much of the world. Many regional forms would evolve.

Domestication, of course, would give the gray wolf lots of opportunities for weirdness to come about. Yes, as weird as the so-called Sardinian dhole was, it was never as bizarrely put together as some of our domestic dog breeds.

These extinct “wolves in parallel” do tell us a lot about how a large canid can radiate across the a broad swathe of the planet and adapt to regional conditions and thrive.




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Clive in Summer Pelt

I haven’t posted much of Clive lately because he’s been shedding out his winter coat. He does not have mange. He really does shed down to these levels.  The areas where he looks hairless are where the fur is about as long as a greyhound’s coat, but it’s much thicker and softer.

This should give you an idea that the red fox is not a bulky, hulking creature at all.

clive in summer pelt

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arctic fox crosses from Norway to Canada

The Guardian reports that an arctic fox has been documented walking 2,000 miles across the sea ice from Spitsbergen in the Svalbard Archipelago to Canada’s Ellesmere Island.

The vixen, a blue phase arctic fox, was collared with a tracking device on Spitsbergen. The Norwegian Polar Institute then followed her travels for the next 76 days. She wandered across the sea ice to Greenland, probably scavenging polar bear kills and catching sea birds. She then wandered across northern Greenland, eventually the sea ice again to settled on Ellesmere.

She traveled an average of 46.3 km per day, which is a little less than 29 miles day. On one day, she traveled  155 km or 96 miles across the ice sheet in Greenland.

Arctic foxes are significantly smaller than red foxes, which kill them where their ranges overlap.  The two species have hybridized in captivity, but the offspring are sterile. Arctic foxes are most closely related to the kit and swift foxes of North America, and they probably could produce fertile hybrids with them if they were ever given the opportunity.

Arctic foxes are not extremely dependent upon sea ice for survival, but the sea ice is useful for augmenting their diets in the winter, when they can follow polar bears.

Because it is unlikely that this fox’s journey is but a fluke, sea ice has been essential in retaining gene flow in the species across northern Eurasia and North America. More research must be performed on the genetics of this species, but it would surprise me if there wasn’t at least some gene flow across the arctic.

Arctic foxes are about the size of a toy dog, averaging 6-7 pounds in weight, but they are so well-adapted to long-distance travel that they can make such amazing journeys.

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This video shows coyotes hunting very much like larger wolves, but it also shows you an odd thing about mule deer.

Mule deer stick together. Mule deer that are not related to a fawn will come in to defend it, while white-tail does defend only their fawns. This makes some sense. White-tails evolved in dense forests where it was pretty easy to hide fawns, while mule deer evolved in open country. Kin selection would favor the genes of mule deer that were willing to come in and defend fawns of related does.

So this is really amazing footage, which shows can cooperatively hunt very much like wolves. These are Western coyotes, which typically aren’t thought of as pack-hunters, but under certain conditions, they absolutely can work as a pack.

I like the way this elk hunter clearly stated that we shouldn’t kill every coyote we see and definitely sees a place for them in the ecosystem.

Mule deer aren’t as numerous as they once were. They have definite habitat requirements, unlike white-tails, which live in virtually every town in the East. Since wolves have been extirpated from most of the West, is it possible that increased coyote numbers could be affecting mule deer populations (even at the margins)?

We know that when wolves came to Yellowstone, they cut the coyote population by half.  Wolves are not major predators of pronghorn, but coyotes take many of their fawns.  When wolves kicked the coyote numbers down a bit, the pronghorn population began to recover significantly.

Wolves certainly do hunt mule deer, but in the West, they have options to go after elk and moose.  Coyotes might take elk and moose calves, but they aren’t likely to be a problem for most mature individuals.

Maybe something similar is going here, but I should caution that the real problem facing mule deer in the West is habitat loss, and although predator control can fix the problem at the margins, it won’t solve the habitat problem.


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