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Archive for December, 2019

She was 8 months old on Christmas Day.

dare looking good

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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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galante and wolf

Forrest Galante hanging out with a socialized wolf that has features similar to the Southern Rocky Mountains gray wolf.

As long-time readers of this blog know, I am a huge fan of Forrest Galante’s Extinct or Alive on Animal Planet.  In the new season, he documents the discovery of the Fernandina tortoise, a Galapagos giant tortoise that has been declared extinct in the wild.  He also has found an unusual giant lion in Zimbabwe that has genetics that cannot be described to any known form of lion in Zimbabwe and might be descended from the massive Cape lion of South Africa.

So yeah, I love this show. The most recent episode involved looking for the Southern Rockies gray wolf in the Sierras of California. Some canid had been killing cattle in that part of the world, and when Galante’s team went into the region looking for the animal, they found lots of interesting things. With use of a German shepherd tracking dog, he discovers a massive deer that has been killed by a canid, and later investigations revealed a large canid that left massive tracks in the snow.

He finally captured the animal on trail camera, and he initially thought it was a wolf. But it had too many coyote-like features to suggest that it was pure.  So Galante surmised that this animal was a coywolf.

Now, this raises a lot of questions. One is that no one has ever seen a coyote-wolf cross in the West before. We know that they exist or existed because the genomes of Western wolves suggest some tiny amounts of coyote ancestry. But no one has seen one before in the West.

Further, the first wolf to enter California from Oregon was noted for his friendly relationship with coyotes. This wolf was of the Northwestern wolf subspecies, but it is possible that he passed some genes into the coyote population.  In recent years, wolves have colonized and bred in California. One pack, called the Shasta Pack, mysteriously disappeared, either killed by poachers or just dispersed. It is possible that a survivor of this pack wandered south into the Sierras and bred with a coyote.

So Galante is finding lots of interesting things in the wild.  One thing I did sort of quibble with in the episode is idea that wolves and humans were at constant enmity in indigenous cultures. Yes, there was conflict between hunting man wolves on this continent, but the work of Raymond Pierotti and Brandy Fogg has revealed that many indigenous cultures had a close relationship with wolves, which often bordered on something like a pre-domestication symbiosis. He played up potential conflicts between indigenous people and wolves, but reality was a lot more nuanced than that.

Also, I don’t think most people are aware of the really upsetting discovery that gray wolves and coyotes last shared a common ancestor only around 50,000 years ago and that the two forms of canid have exchanged genes across the continent. That discovery has been sort of paradigm shattering for me. I have never looked at coyotes the same way since it came out.

Wolves and lions were once the most widespread large predators in the world. Depending upon which version of lion taxonomy one prefers, the American lion was either a subspecies of modern lion or a lineage of cave lions, which were a sister species to the modern lion.  If one considers it the former, then lions had a much larger range than gray wolves ever did, but if one considers it the latter, then gray wolves were the most widely distributed large predator.

It should be no surprise that lions and wolves have lots of mysteries lurking in their double helices.  Galante is getting the public to look at these animals with new eyes.  Lots of hidden things are there to be discovered.

More work need to be done to document Galante’s coywolf, but it is something that should be taken seriously.

 

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Miami is learning not to bark at Zoom. She wants to chase him, but he has rules about dogs barking at him. She isn’t a fool, though.

miami and zoom

miami and zoom not please

She’s still very floppy. The ears will be posted soon enough, but I’m enjoying the mongrel-looking ears for now.  When they go up, you will instantly know what she is, but I am enjoying her cute little flops now.

 

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coyote wolf cross.PNG

An F1 cross between a gray wolf and a coyote that was produced through artificial insemination.

A few months ago, I wrote about a discovery that two species of howler monkey have evolved greater genetic divergence in a hybridization zone in southern Mexico. The hybrids were less fit to survive or reproduce, so natural selection has favored those individuals in both species that were genetically more divergent where their ranges overlap. This phenomenon, known as “reinforcement,” is a powerful tool that maintains both species as distinct.

I have been thinking about how this phenomenon may have played out in wolf evolution in North America.  We have found that gray wolves across North America have at least some amount of coyote introgression, which has been revealed in several full genome comparisons.

The wolves that have most evidence of coyote introgression are those that live in areas that were not in the historic range of coyotes, while those with the least coyote introgression tend to be in the areas where gray wolves and coyotes were sympatric.

It is possible that something like reinforcement went on with wolves and coyotes living in the West. Hybrids between gray wolves and coyotes were probably less likely to be able to bring down large prey or were too large to live on small game, which is the staple diet of most Western coyotes. Over time, reinforcement through natural selection could have caused greater genetic differences between Western wolves and coyotes, and Eastern wolves were without coyote and thus never developed these greater genetic differences.

When coyotes came into the East, they mated with relict wolves, so that we now have whole populations of wolf with significant coyote ancestry.

Now, this idea is not one that I find entirely convincing. One is that ancient mitochrondrial DNA analysis from wolves in the East suggests they had coyote-like MtDNA, which, of course, leads to the idea that the wolves of the East were a distinct species.

Further, the discovery of the recent origins of the coyote makes all of this much more murky.  Again, reinforcement is a process that is only just now being sussed out in the literature, and gray wolves and coyotes are unique in how much introgression exists between them.  Their hybridization has essentially been documented across a continent. The only wolves that have no evidence of coyote ancestry live on the Queen Elizabeth Islands of the Canadian arctic. No coyotes have ever lived on these islands, so they have never introgressed into the wolf population.

The howler monkeys in the reinforcement study hybridize only along a narrow zone in the Mexican state of Tabasco. They are also much more genetically distinct than wolves and coyotes are. The monkeys diverged 3 million years ago, but the current estimate of when gray wolves and coyotes shared a common ancestor is around 50,000 years ago.

So gray wolf and coyote “speciation” is a lot more complex than the issues surrounding these monkeys.

But reinforcement is something to think about, even if it doesn’t fit the paradigm exactly.

 

 

 

 

 

 

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The Big Black Dog

Drake is a fit beast these days.

black

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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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